What Kind of Paper Works Best?
The type of paper to use depends on what you plan to do with them. For almost all items, such as collage or jewelry, I'd go with a bright white paper that is slightly thicker than normal. Regular copy paper is about 20 pound, and card stock is normally 60 or 80 pound, so you'd probably want to go with a minimum 28 and preferably 32 pound paper.
I make wooden collage blocks from my collage sheets, and I print the photographs on glossy photograph paper, and the butterflies and other images on matte photograph paper. But that's because I like the images to be raised a little bit and I coat them in about 5 coats of sealer. If you want to use photograph paper, I avoid the super-cheap photo paper, for example from the $1 store, since it will run. HP, Office Depot, and Staples brand are all pretty good, with HP being the best. I often wait until the Sunday paper comes out and I see what good brand is on sale that week.
And of course, you can always simply print with whatever they have and see if you like it.