https://www.pley.com/Create a list of sets you want, and they are shipped to you one at a time. What I wonder about, is the fact that you can "lose" up to 15 pieces of a kit without any penalty. What's to keep me from stealing 15 pieces from every set I get? Some pieces are uncommon, and hard to get in large quantity. I suppose this might be an expensive way to obtain these pieces, so that might discourage that behavior.
It would be interesting to see if this takes off. Seems like a lot of work to get this operation running efficiently, since the returned kits need to be cleaned, verified for part count, and "topped up" for the next user.