I just put in a mixed 21 jersey order with seller Xiezhijia, who has over 2000 transactions and 100% approval rating. Jerseys ended up being $18.99 each with free shipping. I ended up using Paypal to put a buffer between my credit details and them.
Here's how it works - you chat with the seller telling them what you want to order. They'll enter it for you and give you a link. You put in that order and give them the order number so that they can associate what you wanted with it. Then you pay and hopefully in 2-3 weeks the right stuff will show up at your door.
Earlier I ordered 5 Sabres jerseys from a different seller (Xiezhijia didn't have kids sizes). So we'll see how it goes.