As far as storage goes - check in your basement compartments - look in the rear compartment on the passenger side and see if you have a shelf with a built in mount. My rig has the shelf with the mount designed to securely hold the spare.
I am considering buying a spare myself and I found some good prices at a locally owned shop that services trucks. Should be able to buy a 19.5 tire for $200 - $300 and about $150 for an 8 lug steel wheel to match what you have on your rig.
Bubba & Chiquita + Two Vizslas (Barley and Sophie)
2008 Georgetown 315DS SE LTD
2011 Jeep Wrangler Unlimited Rubicon
Sterling All-Terrain Tow Bar - SMI Stay-In-Play Duo
Do What You Like - Like What You Do!