Around here Craigslist always has great deals on fish tanks, usually with all the trimmings. (filter, etc.) You could probably find a much larger tank for under $50. I can get a 30 gln. tank with everything (often including a stand) for that money almost any week on Craigslist.
Really read through what silkiechicken said ... the cycling of a tank is critical. If done correctly you won't lose any fish because you do it before adding fish to the tank.
Since you already have fish in your tank I would suggest taking them back to the store (letting them know that you were sold fish without proper information) and then cycle your tank. Then, get fish that are appropriate to your size tank. And, actually, a 10 gln. is perfect for a betta. You could add a few small tetras with him and have a nice little set up.
If you can't take them back then read about cycling with fish and follow the instructions and hope your fish make it.
Believe me fish keeping can become as addictive as keeping chickens. If I can't be outside watching my chickens and goats ... I sit inside and watch my fish. They are fascinating when put together in a well rounded community.
Really read through what silkiechicken said ... the cycling of a tank is critical. If done correctly you won't lose any fish because you do it before adding fish to the tank.
Since you already have fish in your tank I would suggest taking them back to the store (letting them know that you were sold fish without proper information) and then cycle your tank. Then, get fish that are appropriate to your size tank. And, actually, a 10 gln. is perfect for a betta. You could add a few small tetras with him and have a nice little set up.
If you can't take them back then read about cycling with fish and follow the instructions and hope your fish make it.
Believe me fish keeping can become as addictive as keeping chickens. If I can't be outside watching my chickens and goats ... I sit inside and watch my fish. They are fascinating when put together in a well rounded community.