For the last 10 weeks I have gotten over 700 750ml bottles mostly from restaurants, and another 77 1.5l. I probably got about 8 cases from a wine store from their tastings. And maybe a dozen or two cases from a higher end Italian Restaurant. Almost all of their bottles could be recorked. And another family Italian restaurant has been the motherload though they had some screw tops i had to pitch. I've got 4-6 cases of usable botles a week from them. The guy even brought his bottles from a second restaurant that he has. At least 30 cases from that place.
I think local places are probably better. I tried Olive Garden a few times, but some managers would not find any bottles while another gave me a case. Plus a lot of the bottles are screw tops. I gave up on them after a few trips.
Only problem was i got so many bottles I could not keep up with the cleaning.