It's still possible to trade with $10, depending on the leverage your account is set.
For instance, if your account is set with 1:500 Leverage, you can buy 0.01 Lots of EURAUD at 1.57148 and it would cost $3.14. On the other hand, if you buy the same amount of lots with the same price using a 1:100 Leverage, it will cost you $15.71.
The only limitation that applies is that each Instrument contains different contract sizes and leverages. For example, Indices and Commodities contain lower leverage and would require more funds to execute a position. For further information on that click here.