PolyJet: PolyJet is Stratasys's material jetting 3D printing process, which jets droplets of photopolymer from print heads and cures each layer with UV light.
A PolyJet printer works like an inkjet printer that builds upwards. Print heads lay down tiny droplets of liquid photopolymer, UV lamps cure them at once, and the tray lowers by a fine layer. Several materials can be jetted in the same build, so one part can mix rigid and rubber-like regions, or carry full colour. A gel-like support material fills every overhang and cavity and is washed or water-jetted off afterwards.
What it means for the price
The materials are costly, and support material is used under every overhang and often around the whole part, so support volume can rival model volume. Build time is driven mostly by height; material cost follows model volume plus support volume. Removing the support is labour. A quote that counts only the model material underprices parts with large cavities or undercuts.
Example: a housing with a large internal cavity may use as much support gel as model resin. The figures are an example.
Common confusions
PolyJet is a brand name; the generic process is material jetting. It is not SLA, which cures resin in a vat rather than jetting droplets. Quotometry prices PolyJet today, matte or glossy, with one material per line. See the PolyJet process page and support structures.
Go deeper: How to calculate 3D printing cost, for any process