Wiggle anomaly...
 

I'm in need of some tires (GP4000, of course) so I checked out Wiggle. They had the best price (39.31) so I threw a couple in the cart and went to checkout to see how much shipping was going to be. It showed about $13 for shipping and my total around $93. There was a little message saying I could get free shipping for orders over $100, so I figured I'd throw a couple tubes in also. Once I did that, it said my order qualified for free shipping even though, after removing the $13 shipping the total was less than $100. I figured this would be caught somewhere along the way to payment but it wasn't, so I ended up getting 2 GP4000s, 2 tubes for $91.56...free shipping.

Now...if only I can be sure my Paypal account won't be compromised as the result of placing this order.

I've gotten free shipping for 70-something dollar orders, it seems to fluctuate over time.

Maybe it's the exchange rate...

System might have fluked for a second when checking exchange rate and didn't catch it before you placed the order.

...and now they know....

I ordered on the date of the OP and the tires arrived today. 12 days...that's acceptable.