I've purchased from WDW Merchandising before -- but it's been about 2 years now and I can't remember precisely. I *think* it was around $12 (which makes DS shipping look cheap!)
When I ordered my pins, I ordered pins that were LE -- but they hadn't set in stone that they weren't going to sell those particular pins through the phone. I think if they knew what a big demand there would be on these pins (the gold WDW MM park dangle pin + baby girl and baby boy Mickey Y2K pins), they probably would not have sold them by phone. In fact, I was worried about receiving them because about a day or two after I ordered them, I read on this board that others were trying to buy the pins by phone but were being turned away.
One thing that you might want to do is get the merchandise number for the pins. It took a LONG time for them to find what I wanted because I didn't know the numbers. Also, confirm that the pins are in stock because if you place the order and not all of the pins are in, you're still going to be charged that flat rate (which greatly increases the price per pin.)
Let me know if that answered your questions or if you have any more.
--LM
P.S. Another option is to connect with the people who are standing in line at the DS in the wee hours, waiting for the pins tomorrow. You'd be surprised how many pin collectors are going to WDW at any given time. Last Saturday I met someone in line who was going with his wife to WDW on Wednesday. By Tuesday he and I were back at the mall -- he took some traders of mine to WDW with him. Just a thought...