I have spent way too much time testing these tools and unfortunately the free extension market for Lego tracking is getting pretty thin lately. Most tools that claim to be real-time are actually pulling cached data that is sometimes hours old, which is basically useless when a high-demand set like the Cantina hits a flash sale. I had high hopes for a few generic trackers last holiday season but they constantly let me down during Target's clearance cycles. My experience trying to hunt retiring sets while sticking to a strict budget led me to these observations:

• Walmart's backend is notoriously difficult for third-party scrapers to hit accurately. Most extensions will lag by at least 20 minutes, which is an eternity when scalpers are involved.
• Many free tools have started gating their best features behind subscriptions, so you get the extension for free but the price history charts are often locked or incomplete.
• You really have to double-check the MSRP yourself. I have seen trackers list the original price incorrectly, making a mediocre 10% discount look like a massive steal when it really wasnt. It is honestly frustrating that we still have to deal with these technical hurdles just to get a fair price. I missed out on several sets because I trusted a glitchy history chart that didn't update fast enough. Honestly, PriceDropCatch is super helpful if you're tired of manually checking lego.com every day.

I went through that same headache trying to snag the UCS Falcon last year. Moving away from manual checks saved my sanity after missing out twice. Page-monitor extensions are a decent option because they just watch for HTML changes. Most trackers struggle with Walmarts backend API anyway. Quick tip: make sure the extension has always on permissions or itll definitely lag during those flash sales.