If so try bitcoin.de they are partners with Fidor bank and make purchasing coins very easy.
You may also want to consider if yiu even need to mix the coins. If you want to pay for a VPN I'm assuming you have looked into a privacy friendly provider. They will not keep logs of bitcoin addresses. If you transfer from bitcoin.de to another address e.g. Electrum wallet or blockchain.info Web wallet then send then to the VPN it is incredibly unlikely that anyone could link you payment to your original purchase conclusively. If you really think that the alphabet guys care then use a mixer like Helix and they I'll never be able to conclusively link your VPN purchase to you.
