If you choose to use PayPal you will be directed away from Cool Sheepskin to PayPal's site to put in your card details.
They are PCI DSS compliant. (Payment Card Industry (PCI) Data Security Standard (DSS))
Card payments are processed by Stripe.
Your card details are entered on a secure web page managed by our web hosting service (Big Commerce | www.bigcommerce.com) who are fully PCI DSS compliant (https://www.pcisecuritystandards.org/) and securely transmitted by them to Stripe.
No information about your card is collected by Cool Sheepskin or stored by Big Commerce.
Only secure (SSL | http://en.wikipedia.org/wiki/secure_Sockets_Layer) connections are used when transmitting card and payment details.