I am living near a university with 30 000 students (about 2/3 undergrads, 1/3 postgrads). There are huge notice/poster boards all over campus. I wanted to test if I could make use of these, and got about 30 A3 posters printed (promoting a friends online shop), and hung them up all over the campus (on the notice boards). Nobody has taken them down although weeks have passed. A few got covered by posters that were hung up later, but most of them are still hanging there completely visible. For only the cost of printing, I can have lost of physical ads/posters in areas with high student traffic. There are lots of other big universities nearby, so I guess I might be able to do the same at some of them. Do you have any suggestions how I can monetize this? So far the best idea I have come up with is to promote student-oriented services (i.e. an academic proofreading service, and then use some freelance site to get the proofreading done). Some more ideas would be appreciated!