If the presale fails, you might turn to resale sites like StubHub or Vivid Seats. These are last resorts, not first dates. You’ll pay more, but at least you’ll get in. Some of these sites even have buyer guarantees. That’s better than a random guy outside the venue shouting “I got two! Two hundred each!”
Avoid Craigslist or Facebook Marketplace. Unless you enjoy paying for paper tickets that turn out to be printer samples. You’ve been warned.