justas a note of possible interest - there are great bowls for pretty cheap in thrift stores - i got a big 5 gallon punch bowl that had no cups to go with it and made a great betta tank! way cheaper than going to a pet store for containers and they have many large varied containers.

back in the day when I was breeding bettas for a research project, I'd keep them in anything. There are big plastic pretzel tubs with screw on lids (about 1.5G). I'd punch holes in the top and use those. Also, plastic thrift-store buckets, little tupperware tubs, etc.

great idea!! i have often seen things like that and they seem like great containers.

Make sure it has a lid! Bettas love to jump...often to their deaths.

I dont remember the last time I kept a fish of my own in a tank or container specifically made for fish......just sec, I do. Years ago when I got my first black moor I kept him in a little 2.5 gallon plexi tank the store employee told me would be perfect. Tank and everything cost over $50. If I got him today with the knowledge I have gained (which really isnt much) form many sources, I could have got a 20 gallon tank with everything and him for the same $50.
Edit: my point is that stores charge too much and rarely would I buy from any one of them, your post just made me think of that.