^ Time to get a couple more estimates, they seem like a ripoff. As someone else mentioned it is still about the total price, other companies may just not itemize their billing to this detail, but in addition to price, be sure you are comparing the same gauge of metal. Some of those made on site gutters are pretty thin, thinner than even the contractor grade originals found on many homes.
Gutters are in fact worth scrap metal money, maybe not enough to take one or two, but throw them in a pile and haul a trailer worth at a time, yes. Granted, at the moment scrap metal prices are pretty low, it could make sense for a company with the space to sit on them till prices improve.