I drove around a lot this summer with one of my bettas. I got a cookie type plastic jar with a lid from the thrift store, cleaned it out well and set it in a box. The container cost me $1 and it was a very effective travel house for my fishy.
Girls girls girls! Shiven, Sheila, Tatters, Kanji, Sitka, Popu, Bass
Boys! Zoot, Mizgarth, Vargus