I have a few french doors, metal clad, have no problems with dents, they are over 3 yrs old. Don't think they dent that easy.
Reccently picked up a 6' wide Andersen, off Craigslist, in pretty good shape, no dents $175.--, transport may be a probelm. I hauled the frame on top my Suburban doors inside.
Home Depot, Lowes do installs even if not bought there. At least in my area, SW PA.
Don't know pricing, I do all of my work around house.
There must be moderation in everything, including moderation.