$BTC Bitcoin (BTC) is the first and most well-known cryptocurrency, often called digital gold. Investing $100 in BTC is a great way to start exploring the world of crypto. To buy, choose a trusted exchange like Coinbase, Binance, or Kraken. Create an account, verify your identity, and deposit $100 using a debit card or bank transfer. Once you buy BTC, you’ll own a small fraction, as one full Bitcoin is very expensive. Store your BTC in a secure wallet, either online or on a hardware device. Bitcoin is volatile, so invest wisely and always research before making any financial decisions.