I examined the pricing on these things. Dry-erase is an expensive process, especially on plastic (very, VERY few companies make dry-erase that sticks to plastic). Then you throw in a tight tolerance tile (expensive to make) and then make it 1/8" thick (lots of plastic, i.e. expensive), you end up with a product that has a pretty big up front cost.
But look at the cost relative to a competitor. A megamat of the same size runs around $35.00. These are $49.95 + S&H (that's where you get the $60.00; if you don't like the S&H, get your local game store to order some), so the base price is only around $15.00 different. But look what you get for $15.00. Dry-erase (Oh yeah!

, easy to draw on, easy to erase,
easy to edit with the wipe of a finger, and no more inked up fingers when you erase), modular (let's you pre-draw the dungeon and reveal it in sections, plus you don't have to erase the whole thing when you run out of room, just move the tiles you aren't using anymore), it's a flat tile (no more miniatures trying on balance on the "waves" that a mat makes when you roll it up) and they are tough (no more bleed through if you get a hole in the mat).