the charges in magicwallet is vary, depending on the price of bts, bitcny come from collateralize bts, if bts price go down, then there will be less people willing to be the gateway, thus the price of converting fiat into bitcny will include a high fee (sometimes 1-2%), but when bts price is going up, like recently, the fee of fiat-bitcny could be very low (because people are feel more safe to collateralize their bts for bitcny and become a gateway), and could even be negative (yes, meaning 100 yuan could convert to like 105 bitcny)