Had a chat with Data Discs, and they are collaborating with Yuzo Koshiro on more of his soundtracks, he confirmed Streets of Rage 2&3 are coming, also stuff they won't talk about yet! I said I was hoping for Actraiser, all I got was "that's a good call" ha. Nice blokes.
Kind of regretting only getting the SoR vinyl now. Then again, if I got both, I would feel compelled to buy every release they come out with...so my wallet am cry less if I just pick the releases from the games I especially love.
I can't really say anything about reasonable prices, but there's some sales history available on Discogs. They don't seem to move much so there's not a lot of data. I guess eBay is worth keeping an eye on, too.
BTW the link I posted should always list any copies of that release being sold, so you might want to check it every now and then.