Define low cost. For me, 1500 dollar is a low cost for a gaming PC.
I can't give you any recommendations, but I can advice you to not buy a used laptop, UNLESS it's from a person you can trust. They will probably sell it to you for an even lower price.
I can look up some gaming laptops and see which one I would recommend, but I need to have an idea what your budget is. Also tell me what operating system you want to work with. I am a bit biased, but I'm guessing you'd want to have Windows for your gaming laptop.