I set up an account with Fedex. I don't ship in bulk but I still get a discount if I print my shipping labels on the computer. I ship in an 8" by 8" by 8" box. This allows room for frogs, a free isopod culture, styrofoam insulation, and 4 phase 22 paks.
Skip insurance as they won't stand behind a live shipment anyway.
Pay for standard overnight shipping BUT choose the "HOLD AT LOCATION" option. This gives you an automatic free upgrade to morning delivery. They are usually ready for your customer to pick up by 9 or 10 AM. HOLD AT LOCATION also keeps your frogs off a hot, bouncy truck and instead, in a nice temp controlled office.
My shipping charges for this average $45 to $50. This allows me to charge a flat $65 shipping and use the extra $15 or $20 for the 4 phase paks and shipping materials. If you wanted to, you could offer to refund the $15 or $20 upon the return of your box and phase paks but by the time they pay shipping on that, they are only saving about $10.