I don't know if anyone posted the exact same thing before, but here's a simple idea for a very usable sled and it will cost you next to nothing. First of all, you need an old tire. Make a hole in the middle of the tire big enough for you to loop a small chain through it, as you can see in the first picture:
Next, you need some kind of base on the bottom of the sled so you can load it. I made a simple cross by nailing two wooden boards together. The boards are just long enough to barely fit into the tire with the right angle and a small amount of force. That ensures the base won't be able to slip out of the tire while you're dragging it and it will safely hold any type of load you will be using. Next two pictures will clear things up:
And there you have it! I've been using it for my HP MASS eccentric-less training and it works like a charm! You can load it with plates, sandbags or just about anything that will fit inside the tire. Obviously, if you need a bigger sled you can simply use a bigger tire.
The final picture shows it loaded with some mini sandbags and a small plate, with TRX attached to the chain:
Eccentric-less training rules, I hope this helps someone who doesn't own a sled to make one very easily. Thanks for your attention!