But some wallets has fixed amount like bx.in.th and btc-e i have the idea because i used them. They have fixed amount of fess like bx.in has .002 btc and btc-e has .001 regardless how much btc you are sending
I prefer wallets that have a fixed fee for all transactions regardless of the amount as when you see a large amount, the fee appears very small but if you are sending or receiving small amounts, the fee becomes an issue.