Before you click 'buy' or swipe your card, run through this checklist. It takes two minutes and can save you from a bad purchase.

• Age requirement: You must be 21 or older. If you're younger, don't attempt to buy.
• Valid ID: Have a driver's license, state ID, or passport ready. Online, you'll likely get an email or text asking you to verify your age.
• Seller's compliance: Look for a clear age verification policy on the website. Legit sellers will mention it. If they don't, walk away.
• Physical address: A real business address on their contact page is a good sign. PO boxes only? Be cautious.