The Point Value (PV) or price of something is a guess of how dangerous it is. Nearly everything has a PV that is intrinsic to itself, or can be calculated by summing up the PV of its constituent parts. Personal equipment, including armor, weapons and even treasure, all carry a PV; a monster's PV scales with its lethality, and the base price of a mecha is its PV itself. You will never see a Monstrous for $2.
Characters have a PV based on their attributes and skills, so that gifted pilots increase the total PV of the mecha they are in.
PV itself is used to measure the worth of a mission; if one is employed to tackle hulking mecha or fierce Hunter-X synths one can expect the pay to be substantial. Experience gained from destroying an enemy is calculated from both the enemy PV and one's own, reflecting the relative difficulty involved.
A mecha with a MV value greater than -4 is 20% more valuable per MV above -4, and the same applies to TR.
The actual cost to buy an item in a shop is the PV by default, but it can be much less if the PC has a good relationship with the shopkeeper and a high Shopping skill. Loot sold back to a shop will go for much less than its PV.
See Guides:Design File Editing#Price / Point Value (PV) for the formulas used to calculate the value of this stat. You can arbitrarily lower or raise an item's price using the Fudge number.