Well a brand new or real clean plastic trash can is my wash tub of choice for sails. Add a real light dose of bleach and trisodium phosphate and you're ready to "mix it up a little" ..Dry well, real well.
I constantly have to beware of wasps beneath the main sailcover and tubes of trailer.
Fiberglassing just isn't that expensive if you do the work, it is labor intensive. I like the doing everything I can myself, a learning experience for sure.
The value of a free boat is of course a moving target. I've seen em' sell cheap on Ebay, and well 30 yr old boats, its very subjective. I could get a free boat and still spend a fortune, there is always something. I could care less about resale I'll probably sink her someday anyway!