Well, it does sound like a really, really, good deal, but this is only the beginning I am sure you realize! It can be a bottomless hole, this hobby!
I got my 55gal tank with filter, light, heater , livestock, food, etc, etc, etc years ago for free from a buddy who was tired of the hobby (was FW, now SW) and I have spent so much money over the years, especially when I switched to SW, and then went reef.
Good luck with the new tank!