At $299, the current price sits close to the realistically attainable floor of $299.86, a level hit 17 times over the past year but held for only 3 days total. Over the full 365-day period, no observed price has actually dropped below today's price.
The absolute low of $263.54 did occur, but it lasted just 0.1 day, making it an unrealistic target for a planned purchase. The price is also quite volatile, changing roughly every 3 days on average, and a drop is currently underway, now in its first day, with about 2 days likely remaining before it ends.
Given the recent 90-day downward trend of 5.9% and the fact that drops of this kind only recur about every 111 days, lasting a median of 3 days, this looks like a reasonable window to act. If the price climbs back above $350, it's better to wait for the next dip rather than hold out for $263.54.