you can start with 500€ on a real account. That's no problem. In this thread I saw formulas like
'To put that into perspective, the value of your trade is : current price x lot size x lots
So in EurUsd at current prices 1.09 x 0.01 x 100 000 = 1090. '
Of course, your profit and loss depends on the lot size and the amount of pips you close your trade in profit or loss. If you can trade with 0.01 lots (that depends on your broker) it should be possible to trade very small profits and losses. (down to cents).
But I suggest to use a tool, that is automatically calculating the possible profit and loss BEFORE you open the order. For newbies, who have no idea about lot-sizes, this is very important! There are a lot of tools like this in the market of mql.
I'm using the Easy Order Creator, because you have here the option to select, if you want to trade directly in lots or in percent of your account balance or as a fixed value in your currency. (e.g. 10 USD). This really helps, if you are a beginner!
There's no need to deal with formulas... ;-)
If you don't want to use an additional tool, you can test your trade with a 'pending order'. Simply place a pending order far away from the actual market price and add stop-loss and take-profit. When you move the mouse afterwards over the take-profit or stop-loss level, a tooltip pops up and shows you the corrsponding profit or loss. With this, you can get an idea of the amount of profit and loss if you open a market order with the same entry to stop-loss distance and same lot size. Or - start with a demo account. This is absolutely risk-free ;-)