Speaking of the landfill strategy, I've been playing quite a bit of Questland lately. You're in a land. You do quests. You gain materials for the crafting/upgrading system. You level up. You upgrade your gear. The devs are very active and seem to be pretty good people.
There are a few types of currency:
money, gained through fighting and the bank; used to upgrade equipment and orbs (which can be attached to equipment; equipment has three orb slots, one for health, attack, and defense)
eternium, gained through fighting and converting excess equipment in the forge; used to upgrade equipment
gems, the premium currency; also gained through many other ways - a small handful through your daily quest completion, spinning on one of the many wheels, and probably a few others; used for expediting trade missions, speeding up your bulk quest thing, buying things from the gem shop, and buying spare uses of the various wheels/random draw functions; I never run out and have accumulated nearly 9k.
guild coinage, gained when donating to your guild; used to buy goodies from the guild shop
honor, barrels, stamps, who the fuck knows what else - currency gained through fighting in the shared quest, trade missions, the arena, and <insert everything else here>; all are used to buy neat things
Back to the landfill strategy thing I mentioned - yes, there are lots of resource types. I don't think you can directly buy any of them besides gems (and even then, I'm pretty sure you can only buy money and eternium (and donate to receive guild money) with them).
I mentioned donating to the guild. You can donate money (easy to get; my bank is giving me a few hundred k a day at this point and the daily guild donation is 50k) for a few goodies and/or gems (50) for a few more goodies. Once enough has been donated, the guild levels up and you can start throwing money into guild-level attack/defense/health bonuses.
As part of one of the intro quests I did a month or two ago, I joined a guild. The guildmaster left and it decided I should be next in line. So now I own a guild. If any DF peeps want to play and get to the level where you can enter a guild, let me know.
I was having fun so I threw $.99 at one of the promotional deals. My purchase didn't go through so I sent an email through the game. The guy on the other end was apologetic and immediately applied my purchase. This was a while ago; they have since fixed the issue.
I noticed a news entry one day. In summary, "This chest is broken; it gives more legendary equipment than it should. To be fair to the people who haven't exploited this, we're leaving it as is. Sorry for the inconvenience."
I received a mass mail from the devs. In summary, "This key is supposed to have a chance to give legendary equipment but we munged the numbers. Here are some free keys to make up for it now that it's fixed." I had not, in fact, purchased or used any at that point.
There's also a divine and busty questgiver lady that you meet at certain points. It's kind of funny - I think she was deliberately designed this way to mock Evony and related ilk.