Where to buy sheet music
There are two "one-stop" sources for woodwind literature that I recommend (with one caveat).
Luyben Music
Van Cott Information Services, supposedly subsumed by Master Music
Something weird is happening with Van Cott/Music Masters. When I first tried to access Van Cott, I was taken to the Music Master site where there was a link to Van Cott publications and VC's original web page had been taken down. Now I find that the MM link is gone and the Van Cott site is back up and apparently doing business as before.
I'll write to him and ask him at some point.
I’ve used Van Cott for decades with outstanding success, though not lately. Gary Van Cott has been especially helpful when I can't find what I need. He'll search for stuff for customers and then order it for us if he can find it.
I go to these services first because I can usually find what I what at one of those two, and I can get what I need immediately.
A caveat: If you're expecting a slick online presence for either source, forget it. The web sites aren't slick at all, the navigation isn't the best, and nothing's pretty about either of them, but they actually stock the stuff they sell, much of it hard to find anywhere else.
If I can't find what I need, I check with individual publishers. Many have an online shopping presence, but I only go to these when I can’t get what I need from Luyben or Van Cott.
I avoid Sheet Music Plus because they rarely keep anything in stock, but order it from the publisher, then ship it to you. That means weeks of waiting. Not only that, but their offerings for single reeds is limited to mainstream stuff that they can make the most profit from with the least effort.
Finally, you can find a lot of stuff free on the IMSLP.org Petrucci Music Library. There's a lot of public domain stuff there (most of the standard single-reed repertoire pre 1900), though not all the transcriptions are well done. Donate! They've save us all a lot of money and heartache.
Over and out.