As a proud new owner of a digital camera, I am now accumulating thousands of pictures (Ok, I exaggerate slightly

) on my hard drive and somewhere along the line I am going to have to get some printed out. Any suggestions for the cheapest and most reliable (if these 2 are not incompatible) providers of printing services.
Printing out my own, except for being able to tweak and crop them, seems rather expensive; 50p per A4 sheet for high quality, glossy photo paper seems about the norm (or does anyone know a cheaper supply).
Browsing the web and checking at Boots suggests that about 15p per 6"x4" print may be about the minumum price; is this correct?
I also noticed that some firms seem to charge much more per print; presumably they will produce them by hand to give the best results.