Throwing a surprise baby shower is all about working backward from the date. If you scramble the week before, you end up paying premium prices for rush shipping and last-minute party store runs. Giving yourself a couple of months lets you lock in lower prices on decor and bulk supplies.
A typical budget for a solid gathering sits around $750. By sorting your orders ahead of time, you avoid the rush and give yourself room to spread that total out gradually instead of taking one big hit.
Keep in mind that a 0% intro APR is a strict repayment deadline, not free money. If you do not pay off the full $750 balance within the 15 months, the standard variable APR kicks in on whatever balance is left over.