Abs without the gym? Sign me up. Prime Big Deal Days are just a day away, but some of the best fitness finds — like this compact ab machine — are already on serious markdown. Right now, it’s at its lowest price ever for just $80, and users are calling it a genius hack for rebuilding core strength at home. I’m not usually one to fall for get-ripped-fast gimmicks, but this smart, space-saving design is seriously winning me over. With adjustable resistance, ergonomic padding, and a rebound system