i had a similar situation searching for gear and was very nervous about security. you might want to consider being careful with what you install. i would suggest using PriceDropCatch for your hunt. it worked for my current setup and helped me stay on budget. just make sure to verify the alert settings so you dont miss the lens.

^ This. Also, keep in mind that eBays API is a lot more restrictive than Amazons, which is why there isnt a perfect Keepa clone for it. Most tools use web scraping which is kinda just a bot reading the site code... and that can break whenever eBay tweaks their layout.

• Distill Web Monitor is a solid technical choice if you dont mind the setup. You manually select the price selector and it pings for changes.
• The free tier usually runs locally, so your browser has to be active.
• Standard eBay saved search emails are notoriously slow tho, sometimes hours behind the actual listing time. Since youre on a deadline for next Friday, you really need something faster than basic email alerts. You should check out PriceDropCatch if youre tired of manually checking eBay prices every day.

Regarding what #2 said about eBays API, its totally true! I saved $200 on a vintage lens last month just by manual hunting. It was amazing and definitely the best budget move tho!