I can't tell the size of the snake either. It would have been nice to have something to see scale.
The cage though seems like more work than good. It is much too tall for a RHP to provide a nice gradient and I don't like that. It also seems really large which means more difficulty in heating and humidity.
All I can do is judge from the pics but IMO I would not take the cage. Not for $100. Unless it has some great stuff coming with it to make it worth something like a nice tstat, light, or RHP. The cabinet itself is not worth anything to me and I would only be using it as a holding cage until the proper home arrived. Then Id junk it.
It would be nothing to build a small perch system out of pvc for a taller tub and set it up in it. I have also found that by using a lamp stand and a heat lamp you can heat a tub just like a glass tank with screen lid. I had to do this when some cages I ordered didn't ship on time and I was in a crunch needing a better home for my big Blood. I put her in a under bed tub with a lamp pointed at an angel on one end. It worked great to give a hotspot, good gradient, and good ambients.