Problem with Checkout & Free Shipping

Let me start by saying, after the recent increase by USPS, I have been having all sorts of issues with shipping on my site. One issue I just discovered is Shopify telling customers who have spent at least $100 there is a shipping charge, when it is actually free. Shopify will pre-populate the shipping charge and then once the customer customer clicks over to the Shipping page they will see the free option. Shopify didn’t used to do that, but now they are and it’s running customers off. I have included two screenshots showing the issue. The first shows a $7.64 shipping charge and then the next shows 3 shipping charges the customer can choose on the Shipping page. How can I make sure customers “Free” shipping is shown during checkout rather than the lowest priced shipping option, which is obviously what Shopify is doing? You can view the problem on my site, SheairButters.com.