if i were you, i would go down to the pet store and pick up:
a 10gal glass aquarium-$10+-
2 aquaclear 20's- $35 (these are hang-on-back filters and should be more than enough for your tank)
thermometer- $1-$3
10-20lbs of live sand- $20
10lbs of live rock- $50-60
Heater(i dono how many watts, i forget)- $15-20
light timer-$5-10
lights-im not the expert but i would say dont spend more than $80... can an expert on the subject chime in for me?
Testing kits- $50
well thats all i can think of, that should get you started. if i forgot anything, let me know. by my calculations, all that stuff costs about $280 and if you get some deals on stuff, you could get it for less. this is an expensive hobby, and i would guess you will be 300+ in the hole before you got your first fish or invert in the tank. hope this helps