Capitalism/Capitalism II - pretty good games of manufacturing/retailing/rebranding, available on gog
I highly recommend the first one. II is basically first game with better graphics and arguably better interface (some say its better some say its worse, or much worse like me) with a few of the features removed (like building between cities - you only have city maps in II, while there is a world map in 1 with climate zones, building positioning to balance transportation costs etc.). Only thing better in II were few fixes to stock market.
And I haven't seen better economic game ever since. I still got a perfectly preserved CD from now non-existant polish gaming magazine "Gambler".
If you want multiplayer, there is browser game called "Economies of Scale" (
http://www.ratjoy.com/ ). Simple, easy and with infinite exponential growth, although quite fun. However it takes a lot of time to get results of your work and cooperation between players is limited. That game really suffers from "not enough
mana players". It leads to little resources on b2b (business to businnes) market or extremly high prices, so everyone just want to produce everything they need by themselves (maybe with the exception of 2 most common resources). It doesn't help that you can sell most items in retail (to non-player population) at least for 10x cost of production over reasonable time (time to get next batch out of factories).