Quote from corvus:
Third, the cost is not significantly different from the futures. Typically, the spread in the 6E is say 2 pips, or $25 + $2.40/contract commission so, ~$30/contract. Margin for one contract 6E is ~$2000. Oanda offers 2-3 pip spreads in the EUR/USD. 3 pips is $30 for a ~$2000 20:1 contract. Yes, this is typically about 2x the ES, with .25 spread = $12.50 + $2.40 = $15/contract and also ~$2000 margin.
Mini accounts would be 1/10th the above retail fx numbers.
Suppose you trade with Oanda the same size you do with futures (125k), then the figures are slightly different: 3 pips will cost you 37,5 $.
As for margin, Oanda has recently made available to their customers 50:1.