Why does it cost $170.00 to ship 2 plastic chairs 42.8 miles from lowes?

They subcontract delivery people.

No way! Does the $170 include the cost of the chairs?

Even with loading and unloading something relatively light, a 42.8 mille trip takes at least an hour and a half to complete. If you're paying someone $18 an hour plus the roughly $10 fuel cost, you're already at $37 cost to deliver that far, that doesn't consider insurance and other maintenance concerns with the vehicle. UPS might deliver 60 packages in that span, depending on population, but Lowe's is probably just got the one trip for your chairs.

Policy and procedures.