You want a drone that takes sharp video and handles well in the wind, not a toy that breaks on day two. Getting the right one means you buy once and keep it for years rather than upgrading six months from now.
Skip the brand new drops. When the manufacturer releases a new version, last year's model drops in price and is usually just as good for hobby flying.
That intro window is a deadline, not free money. If you still have a balance left when the 15 months are up, interest kicks in on the whole original amount.