If your humidity is actually 50% then that is perfectly fine. You will just want it up to 70% during a shed.

Your snake is probably not eating because you are not providing secure enough hides and/or the temps are not right.

You are going to have to spend a bit of money buy hopefully not too much. If you can, I would ask if your mom would be willing to help cover some of the costs.

You will need a reptile thermostat when you get a UTH so I would get one as soon as possible. The reptitemp 500r is widely available online and costs about $20. They are very hard to come across in stores.

You will need a digital thermometer and hygrometer asap. The accurite weather station can be found at the home depot, lowes, and walmart for around $12. It measures two temperatures and humidity so this is the only unit you will need to take measurements.

Please take the heat rock out. Those have only been known to cause problems like burns or even death. They are not safe ever.

Half log hides aren't suitable for BPs because they are just too open. Ball pythons like the "rock cave" kind of hides better but you can be thrifty and use up turned opaque plastic bowls instead. Check out the dollar store for some very good deals. Make sure you get two identical hides, one for the cool side and one for the warm side.

Good luck! I hope you can get things sorted out for your new little guy!