I bought this Ryobi One+ Corner Sander to take down a worksurface prior to re-oiling and wanted something precise for the corners and edges.
I dont have a problem buying replacement sheets for it but then why buy something that you cant source parts for locally.
The main drawback I have is the bag on the exhaust that serves no purpose that I can see, Particles produced by even the coursest of the papers pass straight through it. It may, just may be of a close enough weave to slow down small bricks, but if you are looking for a dust contrlooed sander this is not it. The hose of a Dyson vacuum cleaner does sort of fit up its chuff, but you need to hold it in place, at this point the sander becomes a mess free as sanding is ever going to be.

Ryobi One+ Corner Sander was very good and cheap, But since the sheets are not readily available at popular stores, I would not buy this product if I was you if you want cheap sanding sheets.