Locate a high tech world with a low law level. Purchase as many PGMPs as 
possible, although there may only be one at first. Then, go to a lower 
tech, higher law level world and sell the merchandise. The best planets
for this trick are: LLUN/EFATE (use the trader character on the disk to 
buy a PGMP for 130,500 credits) and STUR/EFATE (There is a PGMP on the 
floor NESAR the gun shop, but they can be sold for 244,500 credits). 
Because you will remain the same system, it is easy to build extra money
using this technique.