If you bought a Synthex's kit before 22th January 2009, the price of the kit only included charges to cover Synthex's expenses. If you bought it after 22th January 2009, the price of the kit includes a small, 10 Euros, donation to the MegaDrum project.
I have not given a permission to anybody else to sell MegaDrum kits/modules standalone or as a part of another product.