If you just need something for your laptop try one of these...

[Link: bhphotovideo.com]

The next step up in size IMO is what Ernie linked to. I normally go with a 4X4' "card table".

Off topic...

Years ago (2011) in New York i bought myself a nice office chair for a big install. I was there for a few months. I stored it with a card table in the crawl space. This summer i went back for service after a lightning strike. I had forgotten about the office chair. What a nice surprise. So much nicer than the cheap folding chairs.