Here is an affordable, adjustable sled that helps you work on your endurance and strength. The UBOWAY Sled Trainer comes with 4 PVC fill sandbags that you can fill with 10lbs each. It has a 360-degree belt ring that lets you train in multiple directions.
Thanks to this sled trainer, you can work on your explosiveness, speed, leg strength, and endurance. You can find out more about it here.