Welcome to the forum
As mentioned already, buy MAID with BTC on poloniex, then send them to a bitcoin key pairing where you control the private key. When you need to send them somewhere you can just import that bitcoin private key into ‘omni wallet’ and the omni wallet protocol will recognise the MAID in there and allow you to send them wherever you want…
Project Decorum (decentralised social network)
SAFE-FS (SAFE File Share)
Project N99 (creative content distribution)
You can buy PDC on Bittrex, but SAFE-FS or Seeds would have to be bought OTC for now as they’re not listed on any exchanges yet.