So for a while I've been using two 2x4 plastic folding tables pushed together as a gaming surface, with a mat on top. It has been "decent" but not great, and obviously not big enough for larger games like 40K or Kings of War.
I decided to try and rectify that, but as cheaply as I could. I didn't want wood, because wood is heavy. Basically. I liked the idea of something light and easy to move or even dispose of. I also reasoned that if I used insulation foam board and put a FAT mat on it, the mat would protect it quite nicely from dents etc.
Here's where I landed with it:
The two tables, clamped together from the underside, with a piece of no-slip carpet runner to help the insulation board not slide all over the place.
The foam board on top of that:
My biggest (but also flattest/lightest) mat on top of that: Mars mat by P.Works:
Then I basically added my smaller mats on top of each other to (a) weigh down the table and (b) keep everything flat. The idea being I can remove mats to get to whichever one I want to play on at a given time. The weight of the FAT mats (there are two of them here) plus the non-slip material seem to help keep the table nicely in place. I'm quite happy with this solution (for now)!