check local fish stores or walmart. based off your post it will probably be your best bet. lots of tanks like these on ebay and such as well.
it MAY be cheaper to buy a small used tank off craigslist or ebay and build it yourself.
IE i have 2 7.5 gal tanks total cost was like 100$ each. i also have a 122 gal tank i built. Filter lights heater i spent 120$. aquariums never end up cheap. once you have the tank you start spending money. various chemicals to make the water habitable, fish substrate decor and test kits. before you decided to buy something make sure it is truely what u want. a 10 gal tank cant hold much in the way of fish. Before jumping into something decide what you really want and go from there.
All 3 tanks were a total of 330$ approx. but since then ive spent around 250$ in hoses and connectors, Co2 (home made) test kit, chemicals and decor and little fish and plants.