im a beginner and i hve what probably a simple question
The cryptocurrency market isn't special, things work the same as they would in any other market.  

It makes no difference how much you buy, nor what you buy (ie, bitcoin, an altcoin, Euros, a house, whatever).  Your profit is how much you sell for minus how much you invested.  So if you buy $40 worth of bitcoin, and sell for $50, you've made $10 profit (minus taxes and fees).