I have the heavy hitch cart mainly to store my Heavy Hitch. For everything else I pretty much mod $20 furniture dollies from box stores. With a furniture Dollie and a couple of small pieces of 3/4 ply wood you could make a nice little cart. You cold als use some 2x4 lumber and a piece of metal strap. Still around $30 in materials and some fun labor,
If you let one slip and drop it on your foot, I'll guarantee you will remember where it is!
Seriously, it makes some sense to store heavy things as low as possible particularly if you have children or pets. The 42 lb weights are bad enough but larger ones could really, really hurt someone even falling off a bench. I either leave weights on the ground under a shed or on a box blade.
While I can lift the weights if need be it causes me a lot of pain. So I went with the Heavy Hitch solution. When I need them for rear ballast I just hook and go (with iMatch). If I need them for the front they are at nearly the same height as the front of the tractor and can transfer them fairly easily.
I put mine where ever I need to take them off. If I won't be needing them for some time then I put them on my disk in the barn. Right now they are in the garage on the floor as that is where I took them off because I will be needing them in the not to distant future. Soon as the chipping gets done the chipper comes off and the weights go back on for some FEL work. Weather can't hurt them and they aren't that big to take up much space anywhere. I'm planning on buying the Heavy Hitch to put the weights on but would still do the same in my storage with my weights. It's no biggie.