If you’ve researched the exercise weights market recently, you know that barbells are far from cheap, even on Craigslist and at garage sales. Now there’s a new, more affordable, and easy-to-adjust option available for building your biceps at home: the Super Sandbag, a durable black duffel affixed with various handles and bright yellow bags inside that you fill with as much sand as you want. For $60 (which includes the outer shell and four sand bags that can handle 10 pounds each) and a trip to the beach, you can do curls, squats, lunges, presses, and deadlifts until your muscles are content. And for the most part, the sand stays inside the bag, but it might be best to keep it in your garage to be safe. See sklz.com.