I agree with most of the other posts, I purchased my Top Fin 10 gal. at Wal-Mart for $35, it included a hanging box filter, a heater, florescent light fixture, and bulb,thermometor, fish net, Tetramin The Rich Mix fish food, AquaSafe water conditioner.
I ended up spending an additional $70-$100 stocking the tank though, this included a bio-wheel(to accomidate my box filter)medium sized log, gravel ( I prefer unpainted or undyed gravel, natural is safer, and looks better),
plastic floating plants, a couple of decorations (a gargoyle, and a sign),
air pump and tubing, bubble stick, and a better thermometor (the one included in the tank kit was crappy),
and of course the fish. For the beginner guppies are nice, maybe a male and 3-4 fems. *But beware!!*
They breed worse than rabbits, and once you see the fry, you'll want to save them and raise them, or your other option is to let them get eaten by the adult fish. I made the mistake of putting gups in my very first 10 gal tank, and now I have a spare 2 gal. for raising the fry, and just recieved a 20 gal that I don't know what I'm going to do with yet. Good luck finding and setting up your tank!