I bought my first mat from Tiny Wargames as they had a sale on 3x3 mats, and I thought one that size would be perfect for solo games of Zona Alfa and Last Days: Zombie Apocalypse (I bought their UK urban zombie mat). I was so impressed with it that I bought their US urban mat as well for some variation. The quality is great and they're pretty inexpensive.
More recently, I got into the new Slaine: Kiss My Axe game and thought I'd pick up another few mat for that (more grassy / natural than urban), and I'm equally as impressed with those prints as I am with the print on the urban mats.
I've included a pic of the UK zombie mat from a recent game of Zona Alfa, and as you can see, it looks great.