Does anyone know how much a riprap wall cost?

Question:is it feasable to build/put up a riprap wall on my hill myself? (the hil lis as high as 12 feet)
does it take much experience/knowledge?

Answers:
Cost depends on your area and availability of materials. Make some calls and find out or do a search online and see if you can find some 'do it yourself' information.

Good luck!