Just a repost from the other thread but here's my cheap mat. At first I wanted to make a more permanent solution... but I decided against it for two reasons: 1) I should wait for the game to arrive and try it out before I spend even more $$$ and time 2) I will want a portable solution anyway for when I visit others.
I went to Joann's fabrics and didn't find any star pattern I liked so I just bought a cheap black yard of material and a $1 bottle of white fabric paint (I didn't really think nebula fits for Star Wars). Used a toothbrush to spray white splatter all over. Really could have been finished there, but I chose to go back and add some could effects and "starburst/flare" type stars to give it a little pop. Overall spent $6 and about an hour of time.