Nick; what part of the Bay Area you in?
I'm in Alameda and have known a fair share of scrap yards
in my area over the last 30 years turning in copper as an electrician.
Most if not all are in the business to buy scrap cheap not
selling small items like kegs back to the public.
The legit scrap dealers in the Bay Area will not take kegs for
scrap even if they're cut up into little pieces, only way if the
kegs were melted down into a block not looking anything like a keg.
There are some "dirty scrap yards" that will buy kegs, sell back I don't
know as I don't deal with "dirty scrap yards".
Best to check with Craigs List, garage sales or local friends as brew supply
places are way overpriced as well shipping if far away.
Check with the major brewery manufactures for their rejected kegs.
I've paid between one beer bottle, a six pack to the maximum of $15 for
a 15.5 gallon plus three 7.75 gallon free.