Timing is the main lever for this party. Hosting on a Sunday afternoon means your guests have already eaten lunch, so you only need to provide snacks and a reveal cake. You should book your venue or order custom reveal props at least a month early to avoid rush shipping fees or losing your date.
We can look at the Citi Simplicity® Credit Card (Citi) to help manage these costs. It offers 0% for 18 months on purchases and balance transfers from date of account opening. This lets you buy the supplies now and pay them off in smaller chunks while you prepare for the new arrival.
The 18-month window is a firm cutoff, not a suggestion. If you still have a balance when that period ends, the interest rates will go up significantly and the party will cost you much more than the original $750.