Online Store in Flash

Hi Everyone,

Can anybody advice me what is the best way of implementing shopping facility into Flash? for example the payment procedures, what do they use for that? I mean I saw couple of sites that are done 100% using Flash and they manage to implement secure payment transactions? I heard of this service called Paypal I heard its easy and fast, but how does it work? does this mean that Paypal is the best for Implementing shopping into Flash or is there any better or other solutions? from where I could get a right direction on this matter?