If you're pricing it in the "by the foot" or "10 or 20' rolls" versions, you are likely to find it considerably cheaper if you price the "buy a whole 50' roll" version (hardware or feed stores can usually order this for you even if they don't routinely stock it).
If you are already pricing it in 50' rolls, well, welcome to the price of hardware cloth.
IMO the wire mesh for the run is usually the largest truly-unavoidable expense of the coop -- it is the hardest thing to scrounge, although if you live in a rural area with junk/farm auctions or happen to get *spectacularly* lucky elsewhere, sometimes you CAN get a good secondhand deal.
One option is to use something larger mesh for the upper parts of the run. You don't lose much security at all (in most cases, and if done right) and it can allow you to build a significantly larger run for the same money as opposed to doing like a 6'-tall run fence and top, fully in hardwarecloth.
Good luck, have fun,
Pat