Washington State,East side,they are just hard to find cheap,and I am cheap;)
Check Reno, NV craigslist.
Define cheap. A relatively complete, running 72 Ranchero with minimal to no body rot but needing mechanical attention and cosmetic restoration in and out appears to be in the $3500-$6500 range depending on desirability of trim level, options and color. More demand for 72 than other years of Ranchero, you could possibly get later years or earlier for less.
El Camino has more demand than Ranchero and is harder to find for a low price.