Amazon has a sturdy wall-mounted fold-out desk for $215 that also becomes a full shelving unit when not in use so you can ...

you can pick a wall-mounted desk that folds down when not being used. Investing in a corner desk (also known as a L-shaped desk) could be a wise move if you're dealing with an awkward room shape.

L-shaped desks, like the SHW Home Office Wood Corner Desk, are also excellent space-saving choices ... like the Latitude Run Wall-Mounted Floating Murphy Desk with storage space inside.