You can search for the tags, genres and locations at the top digitally, and if you’re looking for something specific, I recommend you do it. For example, this may help if you want to buy items from your hometown.
Screenshots courtesy of Wired
As with any collectibles, you can find offers on eBay (the occasional ripoffs). This is a great place to buy something very rare and expensive, or on the other side, many super cheap records you are willing to gamble on. Finding jazz records and other fewer genre albums here, I have done well, but if you are looking for something super specific, then the calculations are better for tracking the market and finding good prices.
Screenshot courtesy of Parker Concert Hall
Vinyl ME, please be a lunar record club, you can also purchase one-time records. I love this service because it squeezes out classics that are rare in all genres as well as modern records. The people who work there have a high taste, which means you always send records you might like. When buying On-Offs, I like that these are exclusively marketed, which means your friends are unlikely to have this specific version on their shelf, even if they already have that record.
Screenshot courtesy of Parker Concert Hall
People who remember the pre-flow era will likely recall the tower records that still exist! This is a great record store to see what vinyl will be coming soon and view pre-ordered versions as it is the main publisher of nearly every larger version on the market. Maybe it’s my older nerd, but if you have some nostalgia, it’s fun to shop online at Tower Records and see what funky new music is.