Ok So I used the mail to a friend option to mail out a swap book and a BOB book.  It says quick credit on it w/the check mark. It's not going to charge the other person a credit when it's scanned is it?  It's just proof that I sent it right? I needed the DC for the Swap book.  I wanted pre-printed postage for the BOB because it was 14oz.  I didn't want to drag the kids out into the pouring rain to go to the PO

It will not charge the other person a credit.  I use it all of the time because it is convenient.  I have even used it to send books to people who are not PBS members. 

OK thanks. I was worried when I saw the "you have used quick credit" on the check mark.

It was my understanding that PBS printable postage is not available for BOB and Custom DC ("mail to a friend") transactions.  Per the Help Center:

Can we use this [PBS Printable Postage] for Box-O-Books and Custom DC?

• Not yet, but that will be available very soon!

I did several Custom DC transactions in January, and this was the case; I had to print postage from PayPal.  Unless something has changed recently, if you were able to print a PBS label with postage, there's likely a credit involved somewhere.

My understanding was incorrect ... nevermind :-)

It was my understanding that PBS printable postage is not available for BOB and Custom DC ("mail to a friend") transactions.

Custom DC and "mail to a friend" are two different things.  You cannot use the Custom DC option to print postage, but you can print postage with the "mail to a friend" option.  I've been doing it since printable postage became available.  There is no credit exchanged.

Color me corrected -- thanks Danielle! :-)

What I did was I reposted the book to my shelf and then immediately hit the mail to a friend.  Then I printed out a label to the person I was doing the BOB with.  It was much faster than going to the post office.  The book was removed from my shelf when I completed the mail to a friend option.  But then I saw the "quick credit" check mark and I was worried. 

Nope, don't worry Mary. :)   I've probably done about 100 of these, and a credit has never been taken from/given to anyone.  You'll see the book also appears under your "en route to me" tab as well as your "books I've mailed" tab.  So, your recipient isn't actually the one who marks it received, you are.  It  looks like  the system is set up to act like you are actually shipping the book to yourself (probably to avoid the whole credit issue all together).  So, I guess if anyone was going to be spending a credit on it, it would be you, and then you'd just be giving it right back to yourself. ;)