2000 Toyota Solara squeaking noise

Hi, thanks for your time. I tried to find to find a previously submitted Q/A for this, but didn't.

My car makes a high, scattered squeaking noise as I drive-- but only when going over a bumpy surface (as if something's loose). It doesn't sound like an engine problem, as acceleration etc. Doesn't impact/increase the squeak. I can only hear it from the inside of the car if my music's off, can't hear it if I roll down the window. The squeak has become more prevalent over the months. I've wanted to take it in, but don't want to until I get some kind of idea what's going on so as to save a pricey diagnosis session! Plus I'm female and some mechanics like to try and rip me off, so I'd like to sound knowledgeable when I go in. :)