Toolpath: A toolpath is the route a cutting tool follows through material, generated by CAM software from the part model and turned into machine code.
CAM software takes the 3D model, a set of tools and a choice of strategies (roughing, finishing, drilling, contouring) and computes every move the machine will make. A post-processor then writes those moves as G-code for the specific machine. Programming toolpaths is skilled work, and it is part of the setup cost of every new part.
What it means for the price
Toolpaths decide cycle time. Roughing strategies set how fast material comes out, which is the material removal rate. Finishing passes set surface quality, and their time grows with surface area and with how small the step between passes is. Small inside radii force small tools and slow, shallow cuts. A quote made without programming the part estimates cycle time from features and the volume to remove instead of from real toolpaths, which is why instant CNC prices need careful calibration against real jobs.
Example: finishing a curved surface with a 0.2 mm step-over takes about twice as many passes as with a 0.4 mm step-over. The figures are an example.
Common confusions
In 3D printing the path a slicer writes is also called a toolpath. The idea is the same, the machines different. Read what drives CNC machining cost.
Go deeper: What drives CNC machining cost, and how estimators work it out