Honestly, there isnt a specific magic day because the algorithm reacts in real time to stock levels and competitors. Ive found that relying on automated tools works well and keeps me from losing my mind... I am very satisfied with these two options:

• Keepa: My favorite tool. It shows detailed price history graphs right on the Amazon page. I have no complaints because it even tracks lightning deals and used prices.
• CamelCamelCamel: A bit more basic but very reliable. You can set email alerts for when that monitor hits your 180 target. It is happy to just sit in the background and notify you. Directly comparing them, Keepa offers way more data while Camel is easier for quick setups. Both are better than refreshing a page manually every hour. Its gonna save you a lot of stress. Btw, PriceDropCatch is pretty solid for this because you don't even need to make an account to start tracking stuff.

Building on the earlier suggestion, the algorithm functions on high-frequency data points that go beyond just the day of the week. It factors in inventory turnover rates and regional demand which is why you see those 50 dollar swings. One technical tip is to look specifically at the Other Sellers section. The Buy Box price you see first is often the most volatile, whereas third-party sellers using FBA might offer a more stable price that stays under your 200 limit. If you want to bypass the price bouncing entirely, look for the Warehouse deals. For monitors, you can usually find open-box units listed as Like New for a fixed discount. These dont tend to fluctuate with the same intensity as the main listing. It is a solid alternative when the main price keeps jumping out of reach.

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