Shipping reptiles isn't cheap as they are seriously expedited shipments. Get the proper box sized for the amount/size of your animals and a couple of extra snake bags. Follow the packing and shipping procedures on SYR and you'll be fine. Most breeders charge around $50 to ship a single animal so $60 to ship four is reasonable. Using the correct shipping methods is well worth the money. Whatever you do don't try to find alternative methods due to cost as it's not worth the risk.
I'm sure others with tons of shipping experience will chime in here. Good luck.