I'm the self proclaimed KING of Craigslist. Last week, I got a 29 biocube with stand for $40. Multiple 55 tanks for free. One came with lid and 4ft coral life light!! Best ever was a leaking 180 with hand made oak stand and matching canopy...for $40. Insane.
I got a 72g bowfront complete setup for free. I also drove up to some guys house once to pickup 2 90g's for free but when I got their he told me someone else was already coming to pick them up.
I actually have not gotten super great deals off CL. The best deal I ever got was a free 55gal that was on the curb of someone house - I noticed it when I was walking my dog. I took the dog back home and picked up the tank lol
Best deal so far was a 30 gallon long with a 300 watt odyssea heater for 20 bucks. The thing that made it a great cl deal was the guy only lived 2 blocks away from my house. Haha what a deal huh?