re: Is there a website where you can determine how “rare” vinyl is?

Many records from the ‘80’s have been reissued—go to elusiveDisc or Music Direct and buy new if possible—you can also get 15% off all the time.

Check out places like Euclid in NOLA—they have thousands and thousands of LPs from every decade and genre.

Also, for things that may be a bit more rare, look at Amoeba Records online (Los Angeles and San Fran), and Forever Young in Arlington, TX (this place is frigging HUGE—13,000 sq. ft.—and they always get a ton of RSD releases and have many trade in collections)