I have a wee Black & Decker single-hand random orbital sander that I love. I do have a bigger two-hander and various other non-random orbitals, but the wee one is the handiest of the lot. You can sand stuff in awkward positions that the bigger ones can't get at, and its dust filter/bag seems to do do a great job. Runs off mains, which isn't what you want but that does make it lighter.
Never thought I'd recommend a modern B&D but there you go.
Looks a bit like
this but the switch is built into the top and works when you grip it. There's a slider to block it.
ETA: cost around 45€