To be honest I kind of make up prices as I go along but for a basic "food" or "drink" it's about 5 to 10 coppers. Think of that as paying for a basic meal like bread or a hunk of meat or something else. Exactly what food you get is basically just fluff, the important thing is you got one food item which would help heal. A slightly nicer meal might be 15 to 20 coppers and and even more expensive might be like 30 to 50 coppers. Think real life if you bought a cheaper meal it might only be five or ten dollars but a more expensive meal like a nice steak with some lobster might be more around thirty dollars and at some places more if you are paying for atmosphere.
50 copper isn't necessary his life savings, that's just what your followers found when they searched the house. Further searching might yield more items or it might not if he hid his valuables outside the house. Also keep in mind, he took you in because he was desperate for money. That means he probably needed the money to spend on something, not just that he likes the way it looks lying in his money box.
Cars like vehicles do exist but are very rare. The majority of transport is composed of flying air/space ships of varying sizes. Taking a commuter ship isn't too expensive and could be compared to taking a bus but riding on the larger ships to get to another planet would be more like an expensive plane ticket. Actually buying a ship is very expensive and usually something only the rich people can afford. Like I said I don't actually have actual price listings written down anywhere but I would probably be thinking around 10 gold for a smaller ship that could hold around 10 people comfortably. Cars are kind of antiquated and you wouldn't really go to a store to buy one but you might find one lying around somewhere if you go about looking.
Banking does not exist in the way we have it today but there would be vault like places where you could pay someone money to hold onto your belongings and loans would be something certain people would be willing to give, especially in the criminal world but with interest. There isn't a stock market or credit cards and the really important people who have lot's of influence, most likely don't even use money, they are probably government regulated Manipulation practitioners who have the government take care of whatever they need and only care about "blood slaves" as currency.
The exchange rate for money is 100 copper for 1 silver and 100 silver for 1 gold and 100 gold for 1 platinum. You are unlikely to need wheelbarrows of coins for expensive purchases because you would just exchange your less valuable currency for more valuable currency. That could be done at a local government official building which would specialize in doing so. Also by the time you actually have enough money where exchanging large amounts is a problem, you probably have followers or workers to go about performing the exchange for you... actually you all already have some followers, so yeah that probably won't be a problem.
A lot of the prices I come up with are somewhat based on real life prices of items but here are some basic outlines.
Bikes really don't exist, you could make one with Manipulation but you wouldn't buy one.
A small ship would be about 10 gold
A computer would be a couple silvers most likely
Hotels depend heavily on the type of location you are staying and how nice it is - for a tavern type of place it would probably just be around 15 to 25 ish
International travel is pretty cheap, think bus type prices in modern day, so it would cost some coppers depending on the distance
Interplanetary would be a few silver
Houses and apartments, think real life price in money costs but with more really cheap options for the lower classes
Clothing is a little more expensive then food being around 20 coppers for cheap clothing and maybe a silver or two for really nice clothing
Yeah I know I don't give too many exact numbers above but I'm going to be making that stuff up when you actually go looking to buy it and a lot of it will depend on what area you are when purchasing and other factors. For the most part I base prices off real life price equivalents to a limited degree.
Technology is advanced in that you can make whatever you want but it's set back by the fact that everything requires sacrifice now. Something functioning like a gun is possible to make but very expensive to create in sacrifice so swords and other less advanced types of equipment are a far more common thing to see. Most armies are outfitted with lots of grunts with armor and shields backed up by very effective siege units that might launch blasts of plasma. Higher ranking officials might be given a spear that shoots lightning in addition to being well crafted for melee combat but that would be too expensive to mass produce and give to the lower ranking people.
The reason there aren't things like official banking and the money used is metal coins, etc is because society kind of fell apart after the void wars. Yeah a lot of it doesn't make sense but society is kind of wacky right now run by crazy despots who run around sacrificing people to make shiny new toys or whatever and they generally couldn't care less about if things make sense or are run smoothly because all they are concerned about is that the sacrifices keep pouring in and that they remain in power. (Besides it makes running the game simple for me
)
The government is comparable to an oligarchy with multiple dictator like guys running individual areas but getting together in councils to determine bigger government related things. The head council person would be very powerful but not exactly a supreme ruler. Government activity is very prevalent and things are sort of like in martial law police state mode. There are lots of soldiers policing the cities and rebellion isn't that common because the gov is ruling by fear and most people would rather be under the rule of the crazy government people that they actually understand then the Void beings that terrify and confuse them. Since the Void wars are still pretty fresh in everyone's heads it makes the atmosphere and everything very fearful. Each of the planets has their own council running it with a Grand Council running all three planets. There is a bit of competition between the different leaders though, especially the more nationalistic ones.
Manipulation is heavily regulated by the government. Since it can do anything, there's a lot of fear about unlicensed practitioners running about doing whatever they want. All the licensed ones have to actually work for the government and perform lots of tasks vital to keeping society running. They make all the big stuff while the people who don't know Manipulation perform lesser tasks. For example, a Manipulation practitioner working for the government might create a machine that paves roads but it requires 3 people to operate that machine which would be where the common people come in to work. There might be machine that takes in energy to create weapons but it would require common people to keep the machine fueled and make sure it doesn't overheat or whatever.
Manipulation created weapons really encompasses everything. Swords, cannons, laser beams and all that is created by Manipulation. Everything is created by Manipulation. The age of technology is past because everyone forgot how technology works. They became so reliant on Manipulation to make and do everything that now they no longer are able to actually put things together or actually smith swords or manufacture vehicles and all that.
Teleportation is common but much more expensive then traveling with vehicles and is pretty much confined to use by the military.
Uhhh alright that was bit unorganized and I might have missed or glossed over a few points but I hope it helped. I'm very busy lately and the only time I really am able to post huge things like this instead of my regular 2 line posts in late at night around 1-3 when I'm exhausted. Same goes for writing the turns so I'm sorry if I make any mistakes... like yeah your Manipulation skill progress should be higher and I'll change that. So if I missed anything, sorry about that, let me know and I apologize in advance.
Edit: Just wanted to say that it's pretty easy to forge copper coins and even make ones that could fool a government official. Silvers are sort of hard to make where they fool a gov official and after that it gets pretty hard to make good counterfeit money.