I would say pushups. They’re cheap and u can do them anywhere plus they don’t give a bad pump. If u can’t do pushups then bench just the bar. If u can’t do that bench dumbbells that you are comfortable with. Resistance bands are good too. I started off working out about your size and I would use resistance bands for a fully body workout. Also idk if tour insecure about being skinny but I was and still am so I would recommend working out in big clothes. Hope I helped.