Of course I've used Craigslist before!  You see a listing & it usually has a picture & a price.  You contact them & maybe make a lower offer, but if you're willing to pay what they originally asked for you meet them & it's yours.  I just don't understand the bid thing unless the seller specifically said he'd sell to the highest bidder by Saturday at 7pm or whatever.
Anyway, as far as deals go here in the Raleigh/Durham/Chapel Hill craigslist, that 46 gallon tank is a stellar deal, best I've seen in awhile.  My father & I aren't on speaking terms so it looks like he won't be getting it.  I left a message and he hasn't returned my call.