I found the following protectors and Case available from Amazon for about $12 combined with free shipping.
5-Pack EZGuardZ? AT&T LG THRIVE Screen Protectors (Ultra CLEAR)(EZGuardZ? Packaging)
For AT&T LG Thrive P506 Accessory - Rubber Black Hard Case Cover
Both items on Amazon.com exactly as shown.
The case is not "rubber" but has a rubberized type finish with some grip but will still slide into a pocket. Fit and finish is OK but not beautiful. That is ok because I just beat them up anyway. I have had the phone out of the case a few times but each time you damage the little ledges that snap it together. A few more times and it will be time for a new one.
The screen protectors are just that. With 5 of them I was happy to practice on one to get the proper technique to apply it. Suggest using water with just a touch of dish soap to apply it.
Very first thing I did with my new Thrive was drop it getting it out of the packaging. After starting to charge it, the next thing I did was order a case for it.