Although these payment methods all perform the same function—exchanging traditional currency for bitcoin—they each carry their own set of fees. How to Invest in Bitcoin. Buy Bitcoin Worldwide receives compensation with respect to its referrals for out-bound crypto exchanges and crypto wallet websites. The private key is the password required to buy, sell, and trade the bitcoin in a wallet. If the demand for bitcoin exceeds the rate at which it can be produced, the price will increase. Secure Internet Connection: If you choose to trade bitcoin online, use discretion about when and where you access your digital wallet.