I am not 100% sure when this unlocks (I believe it is after her 2nd request mission is completed) If you "Speak to Sarah" in the Library she will talk about needing help getting rid of some old magazines. You can constantly talk to her to receive 1 Old Magazine from her over and over (100 gold per when sold). To my knowledge this can be done indefinitely while part of Particus Academy.
It's a cheat way to make some cash while just constantly pressing the X button...mindlessly. In about 10 minutes you should get roughly...90-120 Old Magazines. Which is a nice 9k - 12k gold in your pocket.
Like the 40 BP cheat...it takes time...but when you think about making all the +9 gear and fancy things like that...it is a solid investment.