Southwest allows you to purchase Rapid Rewards points if your balance is too low to book a desired flight. Points can be bought in increments online through your Rapid Rewards account. Occasionally, Southwest runs promotions that give bonus points with purchases, improving value. Buying points is generally more expensive than earning them through flying or credit cards, so it’s best used for topping off your account. If you need guidance on whether to buy points or want to check for promotions, call Southwest customer service at 831-298-4213 for advice.