Just a note too, I didn't know all that till coming here & reading along, but.... if you think about it, the 1-gallon bowls are about $10 and I know I can get a 10-gallon tank at Petco for $12. You can still do 100% waterchanges on that 10-g if you want. It's really not all that hard - doesn't take up too much space or have to be expensive - and I think you'll enjoy watching them swim in the bigger space.
Good luck!

.....I've had a number of fish die on me within 24 hrs of bringing home from the national chain stores. I suspect they're extra stressed and often sick - when they die that quickly I tend to figure it's the store - and you can return it for money back. I have much better luck (mortality-rate-wise) with the smaller "local" fish stores.