There is only one official wallet for Gulden which can be downloaded from here.

The purchase of Gulden can be done from within the wallet, but also via brokers and exchanges. 

Gulden is traded on the following exchanges.

• Nocks.com
• Bittrex.com
• GuldenTrader.com

Brokers offering Gulden

• Litebit.eu
• AnyCoinDirect.eu
• Bitcoinmeester.nl