Originally Posted by satellite779

It doesn't have to be less than $200, but less than $250. If your charge is between $200 and $250, you'll use the full $200 credit so no need to do another charge.

In general, the trick is to harvest eCredits, and then use them for your flight, paying the difference with a credit card of your choosing.

In your case, it seems you want to buy a $562 ticket and you have a $100 gift card? Just buy a random $300-$350 main cabin (or higher) ticket. Make sure it's not basic economy. Wait for 2 days and cancel for eCredit. Use the $300-350 eCredit to buy your $562 ticket paying the ramining ~$250 with whatever card you want.

The only risk is that your $562 ticket goes up in price while you do that. eCredits are valid for 1year so it makes sense to do the "harvesting" ahead of time. You never know when this trick will stop working.