Buying vs. selling an option

Every option has a buyer and a seller. The buyer pays the premium and gets a right. The seller collects the premium and takes on an obligation: to sell shares at the strike (for a call) or buy them (for a put) if the buyer uses the option.

• Buying: you pay up front. The most you can lose is what you paid.
• Selling: you're paid up front. The most you can make is what you collected.