Remember, a 5 or 10 year old bow was as hi tech as they came 5 or 10 years ago.
My wife shoots 35 lbs bow parker and steel force cut on impact broadheads, and it pounches through a 140 lb deer just fine. I shoot 60 lbs and my arrow goes through a deer even faster! They will all kill a deer.
A bigger bow is easier to shoot, 7+ inch brace is more accurate to shoot. I would say a $150 bow with everything at a pawn shop would be fine, brand is not so important, you must have the correct draw length, get measured at a bow shop. and never get to much poundage. You need to go out and practice .Shoot 100 arrows and at 70# you will not be able to do that. Arrows are very important they must be stright. Buy a dozen practice with 6 and save 6 for hunting.
good luck and have fun, archery is fun!!