The G-10 garage, by Neyland, IS permit only. The "long lot," on the opposite side is pay-to-park, and I've parked in the Neyland Drive lot across from Bridgeview Grill for free (not sure if you are supposed to, or not).
For $5, you can park in the University Center garage (get there a little early) or in the newer garage just across Cumberland adjacent to the World's Fair grounds.
Hope this helps!