14. Stair stepper machine
Stair stepper machine isn’t for people who have weak knees. If your knees are strong, stair stepper machine can make your butt tough and bootylicious in a few weeks.
If you can’t afford a gym membership, consider taking the stairs instead of elevator several times a day. Have some stairs at home? Then you don’t need a stair stepper machine, because you can easily work out at home.