You can always drop in to get a blow-dry without having to book. Sometimes, they do a very good job.
However, the staff vary in standard a good bit. One time the girl who dried my hair could barely hold the brush properly and was pretty much just knocking my head with it. She had no respect for what I wanted, nor had had any intention to carry it out.
I also watched a girl get highlights, which turned out to have a blobby or patchy look along the roots when they were finished; they were a bit of a mess.
The manager doesn't seem particularly bothered about the customers, and I've seen her be quite rude to people.
I think it's worth the extra money to go elsewhere.