I would never get a non-self healing mat unless I was just using it for measurements not for cutting. When you cut on them they slice into the plastic and ruin them!
Even a self-healing mat over time, if you continue to cut in the same place will eventually wear out (just ask my LQS) as their's gets tons of use. But it take a long time to wear one out.
When you use the discount coupon at JoAnn's, you can get a pretty big one for a decent price.
In MHO, I would get the biggest "Self-Healing Mat" that I could afford! Even if the size is a lot smaller.