At the end of your first visit to the icy Planet Hoven you will obtain some Raritanium. Take that Raritanium back to the sewers on Planet Pokitaru and give it to the scientist. In return he will give you the Persuader, which will unlock this trophy.
The Persuader is an illegal black market device that gets you between a 20% and 25% discount at all Gadgetron Vendors, which is a huge saving. Unfortunately this discount does not apply to the R.Y.N.O, because that is not purchased at a Gadgetron Vendor.