Upgraded Battle Map 1, originally uploaded by -Frost-.
I created my battle map from tileboard from Home Depot. It costs about $11.00 for a 4 ft. x 8 ft. sheet. It is a heck of a deal, although toting it home might be a problem. I crammed mine into the back of my Jeep Cherokee and that was an adventure to say the least. I had to cruise down the interstate hunched over like Grandma Betty so that the tileboard could fit in the car. In hindsight, I should have just asked an employee to cut the board into a couple manageable pieces.
To grid the map, I used a dry-wall T-square and an exacto knife. I have found no other way to ensure a permanent grid. Even industrial strength marker has come off. A dry-wall T-square is marked just like a ruler, so that greatly simplifies the process of scoring the 1 inch squares. Go slow, though. Since you are cutting into the board, any mistakes you make are going to be permanent.