Thanks to Tim Ferriss for the idea.
Something similar was asked a few years ago (https://news.ycombinator.com/item?id=7478408) but I'm sure there's plenty more suggestions people would have.
My $40 iPod shuffle provides energy and entertainment for my long workouts. Its great and helped me lose a lot of weight. Super durable and practical. Highly recommended.
Under $20? Condoms. Shower mat that feels like grass. Hand chalk.<p>Under $50? Bicycle lock. Iron skillet.<p>Under $100? Bicycle helmet. Bicycle headlight. Cell phone.