I use Mullvad, paid using BTC that came straight from a tumbler. I don't use it for any nefarious reasons, just wanted to see how such a setup would work. It was surprisingly painless. I think it took 15 minutes in total from moving my btc to the tumbler and having the tumbler move the btc to my Mullvad account.
Am I 100% secure? No, they know what IP I'm connecting from. Is my name attached to the VPN? No, not even close. I suppose if I wanted to further improve my security I wouldn't use my own home network, but public wifi's nearby.
But again, I didn't do it to stay "safe" or anonymous. Just wanted to see how the process would actually be.