Weapons, armor, and some other types of equipment can be constructed as mastercraft objects. The exceptional quality of these objects provides the user a bonus on attack rolls, damage, Defense, or some other characteristic that improves when the object is used.
A mastercraft object that provides a +1 bonus can usually be purchased on the open market as a custom version of a common object. The increased cost of such an object adds +3 to the purchase DC.
A rare few objects are of mastercraft quality even without customization—the off-the-shelf version of the object is of such high quality that it is always provides a bonus of +1. In these cases, the purchase DC is not increased (such objects are already priced higher than similar objects of lower quality).
Mastercraft objects with a bonus of +2 or +3 are not common and are generally not for sale. If a mastercraft +2 object could be found for purchase, its cost would add +6 to the normal purchase DC. The cost of a mastercraft +3 object would add +9 to the normal purchase DC.