What a trade really costs

Every trade has a fee (often 0.1 % on spot), paid when you buy and again when you sell.

There is also the spread: the gap between the best buying price and the best selling price. Buy and sell instantly and you lose the spread, even if the price didn't move. It's tiny on bitcoin and can be large on small coins.

Costs look small on one trade and huge on hundreds. Trading often is the fastest way to give your money to the exchange. Being patient is a strategy.