Try to walk in a shop door as opposed to the front door. I know of this because my friend started a sandblasting business. Some guy asked him to do a boat trailer, after renting a large unit and failing at it, we had to take it down to another blaster to do it for him.
Find the guys working, tell them your situation, and ask if they could do it for $20 or so. I guess there is nothing to prevent the dishonest employee from denying that I had given him anything when I came back to pick them up? The guy in shop looks at it and said $20...turned out he did it on his lunch hour.
Do you or anyone you know, have an electric cement mixer.
I have a 2-bag mixer that i got at Harbor Freight a few years back for about $150.00.
Put the chains inside with some sand and pea-gravel and turn on...will be loud, but in a few hours they will be rust-free and ready to be rinsed with paint-thinner and painted!