A solid custom gaming PC should handle high-frame-rate 1440p or 4K gaming for at least four to five years. You want to buy right the first time so you are not replacing core parts in eighteen months. New graphics cards and processors usually drop in the fall, which means last generation's top-tier parts get steep discounts right around Cyber Monday.
A realistic budget for a build that lasts is around $2200. Instead of dropping that cash all at once right before the holidays, you can spread the cost out across a year and a half using the Citi Simplicity® Credit Card.
A 0% interest window gives you time, not free money. If you still have a balance when those 18 months end, regular interest kicks in on whatever is left, so stick to your $122.22 monthly plan until the balance hits zero.