Similar to winning the lottery, solving hashes essentially comes down to chance—but there are ways to increase your odds of winning in both contests. There’s a long list of factors people may point to in an attempt to explain this. Bitcoins should only be kept in wallets that you control. However, exchanges will let you buy any amount, and you can buy less than one bitcoin. As with other stock trading applications, you pay a small fee for each transaction, buying and selling.