Print the slides with whatever printer you have on paper THEN go to Office Depot or one of the other similar places, have THEM p rint the transparencies for you. I just had to do something very similar for my freakin Psych class, and the cost was almost exactly the same as buying the transparencies and printing them myself, NOT counting the cost of the ink. (IIRC, $.50 for the transparency +$.07 fot the printing (B&W) or $.50 +$.89 for color.) PLUS, if they screw it up, the cost is on them...
Edit: Fixed the first line...You should print what you want to put on transparencies on paper first, THEN have them transfered. Unless you are going to print lots of these, buying a box (IIRC, 45 or 50 was the smallest amount sold at OD) then that just adds to your job costs. It was MUCH cheaper for me to have them print them at about $.57 each, than to spend aobut $35. on a box of transparencies, PLUS the cost of the ink...