The shipping charges are based on the weight of items you order, not on their combined price value. In most cases, you will end up paying less in shipping charges than I actually spend to ship your order -- but I prefer the balance tipping in your favour rather than in mine. It just seems more fair. ;-)
The charges for shipping are broken down as follows:
Weights from 10g to 20g -- $ 1.75
Weights from 30g to 50g -- $ 2.50
Weights from 60g to 90g -- $ 3.10
Weights from 100g to 240g -- $ 6.00
Weights of 250g and above -- $ 8.75
To understand what that means in real life, consider a few examples. If you order one Squared-Circle Spindle, you will pay $2.50 in shipping. If you order a single Fetch Hook, you will pay $1.75 in shipping. If you order one package of silk fibre, you will pay $3.10 in shipping.
The neat thing is that it really is based on weight, not on quantity ordered: if you order all three of the items just listed, the clever PayPal shopping cart will add their weights, and you'll pay a total of $3.10 in shipping.
These shipping prices apply to all shipments, worldwide.
The one exception: wholesale orders will be charged actual shipping costs.