Apparently, you should wait 3 days before actually sending something as this is the period of time paypal reserve to check if the transaction/card are fraudulent/stolen. If a payment turned out to be fraudulent you could lose out if you send it off any sooner apparently.

Someone passed that onto me though, i havent looked into that myself.

Personally, i would not use paypal. The more i learn about it the less i like it, and for people that know what they are doing and the finer aspects of how paypal work, its very easy to rip people off and quite often the sellers wont get a choice in the matter!