https://www.arlo.com/en-us/security-bundles
Save up 20% on security bundles
Home Depot has one of their “bond built in” ceiling fans (that has smartthings integration) listed as a featured item for their memorial day sale:
https://www.bestbuy.com/site/top-deals/smart-home-deals/pcmcat1563302233796.c?id=pcmcat1563302233796
Homeseer has quite a few individual items on sale, including their sensor which fits over an indicator light to let you automate events based on that light going on, off, or changing color. It’s a pretty cool device.
Also their plug-in multi sensor is back in stock and on sale:
They also have an outdoor motion sensor which is specifically intended for use with dumb floodlights and includes a temperature and lux sensor
They usually have an odd “sensor sampler“ bundle which combines a number of these, but right now the individual prices are better than the bundle price because of the May sale.
Nothing posted for ActionTiles or SharpTools yet…
Tagging @joshua_lyon @625alex
Flic has 10-20% off most items. These are now the only button other than the Amazon echo buttons which can trigger an Amazon routine, so you can get smartthings integration that way. They also work with HomeKit. most reviews on these are very good, but they are unquestionably expensive, so not for everybody. I love mine, though, I’m up to eight of them. 
I have three different ones stuck on my wheelchair for different uses.
Ring has a bunch of different bundles on sale:
Costco has a bunch of Samsung products on sale. Nothing specific to smartthings unless you count the galaxy watch, and to be honest I don’t even remember which models have a SmartThings app and which don’t.
https://www.costco.com/samsung-savings.html?&ADBUTLERID=large_banner_samsung
They also have the Rachio 3 irrigation system at $50 off for memorial day. That lists an integration in the smartthings app, but I don’t know what features are exposed.
https://www.costco.com/.product.100481393.html?&ADBUTLERID=medium_half_banner_ranchio
Placeholder Yep, you heard me 
Just posting so @JDRoberts can post again.
Meross has a line of budget-priced Wi-Fi devices with good safety certifications. Some work with HomeKit, some don’t, they all work with smartthings. They sell through Amazon and right now have a bunch of new coupons, probably for memorial day. The coupons will appear as a checkbox on the product page.
Three socket outdoor plug (25% off coupon on product page!):
Garage door opener:
.
Main page:
Many items are sold in multi packs, so the first price you see might be for two or even three of that device.
I have a lot of their products now, and I’ve been very happy with them for when I need a Wi-Fi device.
Switchbot Curtain motor $74
Code: 25SWITCHBOT
Not sure how long this promo will last
It’s back to $99 in Amazon, but it’s still on the $79 promo on the manufacturer site:
SwitchBot Automatic Curtain Opener | Electric Motorized Curtain – SwitchBot International
Remember you need to also have the Switchbot hub in order to get smartthings integration.
They also have two bundle packs on sale.
A) hub pack: one mini hub, two curtain bots, $166
B) performance pack: one mini hub, two curtain bots, one handheld button, one temperature/humidity sensor, $193
SwitchBot Smart Curtain Opener Combo For Bedroom / Living Room – SwitchBot International
You need to add the promo code. I just tested and it still works.
Promo code: 25SWITCHBOT
Down to $28
30% OFF ActionTiles License with coupon 30mdsc21 until June 6th, 2021.
Free 14-day trial available at https://app.ActionTiles.com