Where to Buy
The MULTI-Module project has no affiliation with any particular manufacturer, re-seller, or retailer.
MULTI-Modules can be purchased from many RC equipment retailers. The forum on RC Groups is a good place to ask other other people for their recommendations, as they have first-hand experience with a range of online or local retailers.
If you cannot find a local vendor, Banggood carries a number of different MULTI-Modules at reasonable prices, as do several sellers on Aliexpress.