Where do you buy your vinyl?

EBay and Discogs! I am not afraid to pay less for a VG LP. These often sound as good as those selling for 2 or 3 times the price! Winning eBay auctions can be tricky! My best recent auction score was a German Atlantic pressing of Led Zeppelin 1 for $23.50 + $5 shipping and 7% sales tax, so about $29. Excellent condition for a 50+ year old LP - the cover had some damage.

All good suggestions. Another source can be a record label itself, if their artist roster is to your liking. Sign up for email notifications of new releases and label-wide sales, and of course order enough to qualify for free shipping if offered.

I'm signed up with all the audiophile online dealers for reissues (Acoustic Sounds and Speakers Corner two particular favorites), plus a number of labels whose new releases/artist roster are of musical interest to me (New West, Rep Roc, Acony). 

Directly from record label

Plaid Room Records

Merchbar

Acoustic Sounds

Music Direct

I think the folks above identified plenty of sources. Having a few new clean records is a great idea… so you can understand what a new album sounds like. Also, I would get a couple audiophile recordings. This will help you understand the limits of the format / your system.

I have over 2,000 albums… I am sure 500 are audiophile / special pressings. But the real fun to me, these days is spending time in used record stores. We have a good one where I live. I go down once a month and buy 3 of 4 records. I know how to look at them in reflected light and determine they are in near perfect condition. Then I clean them with my cleaning machine… most of the time they are pristine and noiseless. My average cost is $5 - $8… but from expeditions a couple decades ago I acquired hundreds at $1 to $5… what a rewarding pursuit!

A couple hints. Better turntables, cartridges and phono stages can make vinyl the very best audio source. Dead quiet background, huge soundstage, great dynamics, and natural sound. Also, carefully examined used records can be inexpensive and really rewarding… but a record cleaner really makes this work. At some point it is a good idea,

I buy new LPs from Acoustic Sounds, Amazon, Elusive Disc, and Music Direct.  I occasionally buy used LPs off Discogs but only Mint or Mint minus.  If Amazon's price is competitive and the LP is a Prime offering, then I'll buy it there because of the easy no cost return policy.