I am not sure if this is the correct place to post this, so please forgive me if I've placed it in the incorrect forum!

I am new here, and I am wanting to purchase a product from the renderosity store.
I am wanting to pay using Paypal but I am unsure on the procedure.
What I am wanting to know is, do I add funds to my paypal account, or does it work just like a bank, and they simply take the payment out of my savings account?

Ive had a look around, but nothing is clear to me on how it works. Can someone please help me out?

Thankyou
Ascinct