You can buy temporary (15 minute) holo-emitters to make your ship look like something else with the GPL. You can also buy GLP accolade trophies with it. That's about it for right now.
When doing the Rescue Deferi Captives (sp?) daily, you confront the Breen and one of the options is to pay the Breen in Gold-Pressed Latinum to release the Deferi.
(As Fed, you have the option of not doing this and instead using some kind of sensor pulse to allow you to beam the Deferi to your ship and then leave the area without firing a shot or paying.
As KDF, your only other option seems to be to destroy the Breen ship and then get brow-beaten by your Tac officer if you don't stick around and destroy two more groups of Breen reinforcements.)