I'd sooner start from scratch & build something good- sorry, but I'd run the other way from these.
And not only that, but what I've always said about buying used glass tanks applies here too: you have to wonder what the previous occupants died from, & how on earth are you going to disinfect this?
To me, not worth the risk or the trouble. They remind me of that old movie "The Money Pit" about a couple that buys a huge "bargain" of a house that just needs a few fix-ups- but it turns out to be way more than they bargained for, & not in a good way.