apologies - this looks like it was splitting the order between our two fulfillment warehouses...and charging you shipping twice.
I've fixed it so that even if we have to split the order you're not charged shipping twice.
You're also right, if your order is over $100 then you get free shipping
Lastly, I've updated the inventory of Thermoamp, but we are down to single digits ... we had a shipment expected to arrive before labor day, but it's been delayed. We do have more than 1 in stock, but it's not much more than that