Instead of the Converse shoes, which have a somewhat rigid rubber bottom outsole, consider buying some plain canvas-bottomed shoes. You will wear through all of the layers of canvas within a few months, but if you get them from China (e.g. on Taobao) they only cost like $5–$10 per pair.
Alternately, thin leather moccasins can also often be pretty cheap (or can be made yourself).
If you want something a bit more durable, I find that most styles of Vibram’s finger shoes last a fair while, but plenty of people seem to dislike their appearance.
Sure, there are alternatives. The Cons run about $45 a pair, last about a year, and don't call undue attention to themselves. I find they strike a pretty good balance. Plus, they're Cons :)
Alternately, thin leather moccasins can also often be pretty cheap (or can be made yourself).
If you want something a bit more durable, I find that most styles of Vibram’s finger shoes last a fair while, but plenty of people seem to dislike their appearance.