Slab or Prehung? A slab is just the door; you (or a pro) attach the hinges, drill holes for the hardware, and hang it on an existing jamb. A prehung door comes hinged to a jamb and has a threshold and a weatherstripping system, with the option of a factory-installed lock and latch. You trim it out to suit your house.
What's it Cost? You'll pay anywhere from $150 for a smooth-surfaced, paint-ready slab to $7,000 or more for a prehung, realistically textured and factory-stained wood-grained model with lights and molded panels. The sweet spot for a high-quality fiberglass entry door is $1,500 to $2,500. Add on about $400 to $800 to have a pro install it.
How long will it last? A lifetime warranty is standard; the maker will replace the door if it fails for as long as you own your house. Glass and factory-finish warranties are another story, typically 10 to 20 years and one to three years, respectively.
Where to buy? Order through big-box stores or, for the largest selection of hardware, finish, and glass options, from an independent specialty window and door supplier.