Here is just a small part of their FAQ.
How does buying on Etsy work?
To buy items, you'll need to create an Etsy account (it's free and easy). You purchase items on Etsy directly from the seller, using whatever payment you specify when checking out (e.g. PayPal, money order, check etc.). Keep in mind that every seller must be paid individually, and all payments must be made within seven days of checkout. We ask if you choose to pay via PayPal that you submit payment immediately to the seller. Each seller will have their own return policy (if they have one at all), shipping options and payment terms. If you have any questions about any of these, it's best to contact the seller directly before making the purchase.
How does the shopping cart work?
As you shop around and find items that suit your fancy, add them to your cart. Note: items in your cart are not removed from the site or reserved for you, until you complete the checkout process. The majority of items on Etsy are one-of-a-kind and thus tend to sell out quickly, so it's a bit risky to leave items in your cart for too long. Once you've got everything you want, click the big green Checkout button and following the onscreen instructions.