Great post MAB, a great tool that you can make on your own for very cheap would be a sandbag, I believe athletecreater has a video of some stuff to do with sandbags in another post. I believe that I made mine for under 20 dollars and it was very simple to make, it is around 60-80 pounds. There is a ton of stuff you can do with it, like squats, cleans, overhead press, rows, curls, really anything.
Also you can just find a huge rock and pick it up, my friends and I did a lot of this sort of "caveman" training this summer and it works great, pick up anything throw it, and do it again. Get creative. Just my opinion, you do not need weights to get strong.