I learned something new while I was staying at Disney's Saratoga Springs! The spa there offers a day pass for $25, just like onboard the Disney Ships! The day pass allows you access to the thermal suites (Sauna, steam room, hot tubs, heated loungers) as well as the relaxation room, where guests can chill out and have a small snack.
Did you know that the WDW SENSES Spas did this? I totally didn't know! Now I do though, and I will be indulging regularly.