Late August is the sweet spot for patio gear. Stores need to clear floor space for autumn inventory, so you can often find that $600 fire pit table for a fraction of the price. Getting it now means you have a warm focal point for the backyard before the first chill hits.
Don't just walk into the first big-box store and grab the first box you see. Check three different retailers online and in person. Compare the burner output and construction materials, then use those prices to see if anyone will match a lower offer.
Remember that the 0% window is a deadline, not a gift. If you still have a balance on the card after those 18 months, you will start paying interest on the remaining amount, which will quickly make the table more expensive than you planned.