sounds like you got a deal of a lifetime on that beautiful tank. that is the first step. here go some suggestions...
filter: i love fluval canisters, so i would recommend a fluval 404 ($109) and a bio wheel ($30). this shoud be sufficient
heater: i love ebo jagers. you can get 2 250 w heaters for a grand total of $40
substrate: a thin (1") layer of coarse sandblasting sand (a 100 lb bag is under $10)
lighting: you can get a 4' shop light at a home depot or lowe's for $7 and 2 bulbs made specifially for aquariums at the same place for $5 bucks each
i would also recommend an air pump and bubble wand. you can shop around for these, but the pump and wand should be under $50 or $60
also, i would get glass tops, but you can get creative. the decorations are where you can spend tons of money, or very little.
grand total of necessities: $260
there are many ways to cut costs. check out this thread:
http://64.191.28.50/forums/showthread.php?s=&threadid=342
i wish you the best of luck, and if you decide it isn't for you, let me know.