You are able to trade with a mere $5, as this would depend entirely on your leverage.

You may calculate this yourself by using the equation:

PRICE X LOT SIZE / LEVERAGE

If your leverage is 1:500 and you have purchased 0.01 lots of EURUSD at 1.54832 and that would cost $3.10.

If the price was the same and your leverage was 1:100 instead, it would cost you $15.48.

This would vary depending on the instrument traded due to contract sizes or leverage available. 

For example, Cryptos and Indices have a lower leverage available, therefore, more funds are required to open a trade with them.