Honestly, you arent doing it wrong, Dior and Chanel almost never host sales on their own sites. Its super frustrating. But department stores like Nordstrom or Sephora definitely markdown luxury stuff during holiday events or random beauty promos. Ive been using the Sephora app alerts for a while now and im pretty satisfied with how it works. No complaints here, it has saved me a bunch of cash. You can actually set alerts for specific shades which is super handy. Here is what has worked well for me:

• Put the exact Dior foundation you want on your Sephora Loves list and turn on push notifications.
• Check department store sites like Macys or Nordstrom because they run beauty promos way more often than the brand sites.
• If you get desperate, just walk into a Sephora or Nordstrom in downtown Chicago and ask for a free sample of the foundation. That sample trick has saved me so many times when my budget was tight before a big event. It easily gives you enough product for a couple of days and costs absolutely nothing. Good luck with the wedding, im sure you are gonna look great!

I've spent way too much time analyzing price data points lately. I remember tracking drops for a wedding last year and used this Sephora price tracker because it has low latency. Worked well for me.

• Just get any foundation from Dior
• Grab any lipstick from Chanel The pigment density on those brands is just objectively better for high-res photos, ngl.

Re: "I've spent way too much time analyzing price..." - yeah i feel that. i've been doing this for years and unfortunately luxury brands make it so hard to actually save money. even when you get a notification the good stuff disappears in seconds which is super discouraging. i used to rely on a few different trackers but lately i've had issues with them being too slow. i tried PriceDropCatch recently to keep an eye on some chanel lipsticks and while the alerts are okay it definitely isnt as good as expected when the inventory is that low. you really gotta be fast or you just end up disappointed because the popular shades go first. speaking of chicago weddings tho are you gonna be near the lakefront? i went to one at the planetarium a couple years back and the wind was absolutely brutal. i spent like forty minutes on my hair just for it to look like a birds nest the second i stepped out of the uber. then we tried to find a late night pizza place after the reception and ended up walking like ten blocks in the wrong direction because my phone died. i think we finally found a place but i dont even remember the name... it had those red checkered tablecloths and smelled like old garlic. anyway lol sorry kinda went off topic there. i hope you find what you need for next week!