Is it possible, when a payment is received, it isn't charged, it's only holds the amount.

[Tom61]

Is the following scenario even possible with paypal?

Some of the items we are selling can vary in size. 

When we receive the order from the customer we want to put a hold on the CC for the amount of the order.  We don't want to complete the charge just yet. The order comes from a shopping cart system.

Now that we know what we need for the customer we request and receive the item from the source, weight it and determine the actual price.  We then want to adjust the order total and push through the charge for the correct amount.

[skier · Accepted solution]

You should take a look PayPal's Authorization and Capture feature.  It's explained in PayPal's Website Payments Standard Integration Guide which can be found here.

Regards,

skier

[Tom61]

Thanks skier, that answers my question(s).