The facility (the ShowerTree) in the airport moved about 1 - 1.5 mile offsite. From their
website, the place still looks quite affordable. Since you want to store your luggage, you will have to rent an overnight room which is $22 plus tax. If you only wanted the hot shower, it would only be $7.50 plus tax. They don't have a free shuttle service to/from the airport, but it is on a major bus line or you can walk if you feel like it.
TF