If she wants them WITH the images... charge for the prints... if your 4x5s are $20 each, charge (8x$20) = 160 PLUS 2 or 3 times the material cost of the FOLIO. So, $200 for a full folio makes sense.
Let her know its discounted or even a FREE bonus if she spends more $$
If she just wants the folio with no prints, watermark all of your prints, cause they'll be copied and in the folio.