yesterday I bought a spider ball python and I have some questions:
I know it's long but please please please read and give me your replies.
1. Does this seem odd?

When I went to look at the spider ball I bought yesterday, the guy told me that he doesn't use any substrate and that he puts the UTH under the tank. He wouldn't let me see the tank "because the dogs were in the room with the snakes". His other snake tanks had no substrate either and he had a burmese... no hide.. no heater... no soaking bowl... in a tank I thought was only big enough for a full sized BP. Granted, this burmese was only 5 feet long, but still. The spider I chose felt very cold and looks thin, and probably dehydrated when I held him, so I'm assuming that he was in the same boat as the burmese. He said he's had these snakes since they were hatchlings, sooo my question is.. this is wrong right? is it possible that he's kept these guys alive in these conditions since hatchlings?... None of them appeared to have mites and no signs of an RI in any of them. I went ahead and paid $100 for the spider and brought him home, which again seems odd since I've seen them sold between $400-$500, sometimes more. I had someone else that has morphs look at him right after and they said he is definitely a spider.

The enclosure I now have him in is an under the bed storage unit with ventilation holes all over the top, a UTH, and paper towel for substrate. I don't have a heat lamp because the UTH seems to do great on it's own and I don't feel the need to bake the guy with a light too, but please, correct me if i'm wrong.
Humidity- 70%
Cool side-fluctuating between 70-75 degrees
warm side-fluctuating around 90 degrees
I have his water bowl on the cool side and his hide on top of the UTH. I put my hand on the heating pad and it isn't hot, just warm, nothing that could burn him. (he will not go in it and it is big enough for him to curl up into. I've tried moving it off the UTH for a few hours, he doesn't want to go in it. I've moved it to the cool side, nope, still doesn't want to go in.) I understand he could be stressed, but he moves around his enclosure when he gets his dark time, but curls up in a corner when I put the enclosure out in the light of the room.

2. Feeding...? I don't know what to do...

The guy I bought him from said that he last ate 15 days ago right after his shed.. keep in mind that this snake is thin already. maybe it's just me, but why would he sell the snake to me hungry?.. because now I'm in a stuck spot. i have always waited a week after bringing a snake home before feeding, but this guy is thin already and hasn't eaten for 15 days. plus he is a young age and still growing, and I always fed my juveniles once a week. the person with morphs that I had look at him said that I should definitely feed him by today because he is thin and hasn't eaten in over 2 weeks now. what should i do? Also, the guy that I bought him from feeds him pre-killed and I am so so sorry but i cannot knock a mouse out. i just cannot. I have always fed live.. but everyone at pet shops keeps nagging at me that it takes off 10 years of their life and they can be harmed, but i never ever leave a snake unwatched with live prey. what do you guys think? frozen or live for this guy?