To expand on this, make sure you itch like people with lots of money but no time/knowhow.
For example, hang out at small-town airports or boat harbors, or with lawyers and doctors. If you can find some small part that would help them use their boat, then $300-500 for it might not even be an extreme price especially if they see you using it first.
(This is not an argument to go buy a boat and plane).
Riders of high-end motorcycles as well. People absolutely love customising their motorcycles with things like GPS mounts, bigger/smaller windshields, auxiliary lights, footpeg extensions to make the bike more comfortable for taller/smaller riders, more comfortable seats, etc etc. The market for luggage and luggage mounts is probably quite well served, but especially for rarer or older bikes, it can be difficult to find the more obscure accessories.
For example, hang out at small-town airports or boat harbors, or with lawyers and doctors. If you can find some small part that would help them use their boat, then $300-500 for it might not even be an extreme price especially if they see you using it first.
(This is not an argument to go buy a boat and plane).