From their website:
The Bargain Game Mats webpage is for Game Mats that are either a little less than perfect due to minor imperfections, were prototypes/experimental for later production game mats, or were customer orders where the customer changed their order after their game mat had already been produced. In many cases, the customer changed their minds at the last minute on the hex size they wanted on their custom game mat (this happens more than we would like). In most cases the game mats listed on the Bargain Game Mats webpage are perfect, flawless game mats. If there are imperfections, these are noted in the game mat description. The game mats listed on this page tend to sell quickly so do not hesitate -- what is listed today, may be gone tomorrow.