Ken the bug guy is alright, won't say anything bad there, but check out the classifieds here, you'll find a lot of quality breeders and dealers with some great deals, shipping is usually a lot cheaper as well. As others have said it's just one shipping charge
I've ordered from well over a dozen places, and the shipping rate has always been a flat rate for whatever you buy. Most folks try to order more than one animal to try to get the most out of their shipping. $45 shipping for five spiders is a heck of a lot better than $45 for one.