I just got a price on replacing the carpet in my 20 ft Triton, carpet i ask for a good avg grade nothing fancy just avg, the price was $ 1800.00, is that as high as i think it is? I can't afford that, and i'm broke down, bad knee's & a steel plate in my back .Has anyone had their replaced ?

I recently replaced the carpet in my ranger. It was about $175 in carpet and supplies (glue, box of utility knife blades, scraper and glue brushes). It took three full days off worth of labor to get it done. My old carpet came up nice so I was able to use the old pieces as templates. I used contact cement to stick it down, it worked awesome. 

Unfortunately, if you're going to pay someone to do it that's about the going rate.  I did mine last year and it was about $350 total in supplies for my 20' Stratos...It took me 4 full days to complete.

It's the labor price that drives the cost up when you have someone else do it.  The carpet itself isn't really expensive.  You could try to have them quote you a price with out any materials to see if buying the stuff yourself makes it any better...But I'd guess it would come out to roughly the same total in the end.