It depends on the petco. I just bought a 2.5 gallon mini bow and it was on sale for about $30. An improvement on the regular price but not as nice as $19.99 so you'd have to look at your petco. Also mine came with broken filter which I of course didn't realize until I had already planted the tank. Oh well.
Speaking of the two gallon hex. I have it. My friend gave it to me after er betta died. She didn't give me the filter with it, I'm assuming she tossed it. But I'm actually pretty pleased with the tank itself. It's not actually 2 gallons but rather closer to 1.6. I was a bit disappointed. Looking at my betta in it though I don't feel like he's cramped. He has plenty of room to swim around. If I wasn't planting the tank I would probably stick with it but I wanted a tank with a hood I could put a better bulb in I probably wouldn't be upgrading.
That was my really long winded reply to a question that really didn't need it, but oh well.