I have three mat towels. Two are cheap ones I picked up at Target of all places. The other is a non-cheap yogi toes towel that is - somehow - not as beloved as the two cheap ones. It's pretty and it has little rubber nubies on the bottom, but I just don't like it as much.
The red/grey target mat towels have acquired a patina to them. There's grass from Amarillo, dirt from Taos, and dust from the home studio. (Yes I wash them, but those things are still there. In some form or fashion.)
I've only carried my actual sacred space, the manduka mat I've used for the past year, when I'm traveling specifically for yoga, a retreat or workshop. And, yes, I take it to class when I'm home in Nashville. But when I travel, I always bring along my trusty cheap yoga mat towel. It turns any spot on earth into your own personal sacred space.