Having just seen in another thread that people are looking for this service, and finding it @ $30/sheet, I wanted to mention that a local lab in Phoenix, Colormark (www.colormark.com), does 8x10 for $8/sheet and 5x7 for $5/sheet.
AgX Imaging (www.agximaging.com), in Michigan, which I've also used very satisfactorily, is even cheaper: 8x10 for $4/sheet, and 5x7 for $3/sheet.
I have used these two labs, with which I have no financial connection, for 4x5, and been very happy with the quality of their service. Just wanted to pass along the names of a few labs offering more reasonable prices ($30: wow!). There probably are others as well.