I feel your pain. I live right down the hill from you and the D60's are hard to find and usually super expensive when you do. It took me over a year and half of checking Craigslist on almost a daily basis before I found one that was in good shape and not ridiculously over priced. The best way to find/get one is to check CL or Pirate regularly and try to call/contact the seller the moment you find one you're interested in because they usually go fast... And as mentioned above 75-93 Dodge D60's will work in a Chevy and can be easier to find around us than the GM D60's. Just be aware that that the 89 and down axles had external locking hubs but 90-93 were internal like GM and be cautious of people selling D61's, they look almost identical to a D60 but they have really high gears (3.07) and have a weird pinion offset that makes gear changes a lot more difficult.
There are a couple options out there right now if you don't mind driving a little bit. Best deals I'm seeing at the moment are a D60 front with D70 rear out of a 92 Dodge for $1600 in Stockton (
https://stockton.craigslist.org/pts/6104721288.html ) or a GM D60 with 14 bolt rear for $1600 in San Jose (
https://sfbay.craigslist.org/sby/pts/6112603270.html ). There's also a front D60 from a 92 Dodge listed on Car-part at a wrecker by Vallejo that used to be listed for $990 and now says "call" for the price so it may be cheaper now...