I have been a vinyl collector for many years. The places to look are, of course, used record shops, if any are in your area. If not, pawn shops, Goodwill, Charity stores, flea markets, are all sources. At these places, you might find 1 or 2 good albums that aren't ruined, but I have got some gems too. If you travel to big cities, this is where you can get into the big time. There WILL be used record shops there, and they will be bigger than you ever thought possible. I went into a place in Louisiana once that had 2 million records.There used to be record collector's conventions in auditoriums around the country, where the whole place was filled with used records, sellers, and buyers. I think they advertised in Goldmine Record Newspaper, which is also a good buying source. Alternatively, Ebay, and internet record sellers can reduce the travel for you, but you can't see the record, and have to take their word for the condition. You can advertise in your local paper for buying record collections. The ones you don't want, you can re-sell. Some guys even open up a used record shop, and keep the best stuff for themselves. This is always a good way to get great albums for cheap. That's a couple of suggestions.
