The main types of bets in roulette are inside and outside bets. Inside bets involve placing wagers on specific numbers or small groups of numbers, such as straight-up (a single number), split (two adjacent numbers), street (three numbers in a row), and corner (four numbers in a square). These bets have higher payouts but lower odds of winning. Outside bets cover broader options, including red or black, odd or even, and high or low (1-18 or 19-36). While the payouts for outside bets are smaller, they offer better odds of winning compared to inside bets.