Probably P2P is the cheapest of them all, but the only problem that I feel like plagues the P2P market is that a lot of people are not fair with how they sell and buy their price, they almost always go OP when they're selling and go total cheapskate when they're buying. One example is the USDT P2P market in the Philippines, the price for buying is criminally low, they cut around 14% or so when buying USDT. Of course this issue with Filipino P2P Market won't change the fact that I think that P2P market is the cheapest way to cash out your coins.