It's been my experience that if you add $2/lb to untrimmed Tri-Tip you have the "real" price.
There are some good vids on youtube on how to peal one. After a few.... it goes rather quickly.
Local grocery store did a sale a few weeks ago on choice untrimmed CAB for $3.99/lb.
Might have been some of the best TT I've ever cooked/ate.