Oh I totally understand the hesitation, when my daughter was in preschool, I remember pausing at every little extra charge too, wondering if it was reasonable or if we were being overcharged! Honestly, $18 for school photo-taking sounds pretty standard from what I've heard around, most preschools in Singapore do charge somewhere in that range for the annual photographer session, and it usually covers the printed package they send home. My friend whose child is at a PCF Sparkletots centre mentioned the fees there tend to be quite transparent and not too inflated compared to some private centres. Some mums are fine with it, though a few did mention wishing they could opt out if they didn't want the prints. Hope that helps put your mind at ease a little!