Ugh, the manual refreshing struggle is real. Honestly, PriceDropCatch is the best way I have found to track Buy It Now prices without any extra clutter. It is free, straightforward, and stops you from needing to babysit the browser all day. TL;DR: Set up an alert there and let it email you when the lens hits your 250 price point. Seriously, save your sanity and just let the site do the work.

Honestly, I have been using Keepa for years for stuff like this. People usually associate it with Amazon, but if you look around, you can actually set up custom tracking for pretty much any item you find. I was hunting for a specific Leica lens last year and had the same headache with sellers relisting items constantly to keep them at the top of search results. It drove me nuts. What I did was just use the browser extension to watch the specific listing ID. It is super reliable and honestly just works well without any of those shady signups. I am always a bit paranoid about giving out my info to these random tracking sites, so sticking with a more established tool like that keeps me feeling safe. I really like how it shows you the price history graph too, because sometimes you think you are getting a deal, but looking at the data shows it was actually cheaper two weeks ago. No complaints on my end, it keeps things simple and you dont have to pay a cent. Just set your target price, enable the notification, and walk away. You will get an email the second it dips into your range. Just make sure you check your spam folder every once in a while, sometimes those alerts get buried in there!

Building on the earlier suggestion, I have to respectfully disagree that complex software is the only way to go. Honestly, while those professional tools are powerful, they are complete overkill for someone hunting a single vintage lens. You really need to be careful with browser extensions or third-party apps that ask for extensive permissions just to watch a listing, as that is how your data gets scraped. I would suggest taking a more manual but effective route first. Just save your search on eBay with the specific keywords and filters set, then turn on the push notifications in the app. It is not as granular as a custom tracker, but it hits your phone the second a new listing pops up at your price point. If you want something a bit more robust without the enterprise headache, this eBay price tracker is a solid middle ground that works well for hobbyists and keeps things simple. Just be careful about those sellers who relist constantly. Sometimes they are trying to manipulate the search ranking algorithm to look like a fresh listing. If you see a seller doing that, they are usually desperate for a quick sale, so you might even try sending a polite message with an offer near your 250 limit. Most of the time they will bite if they have been sitting on the lens for months anyway.