Meross 4 pack MSS110 16A pocket socket for $25. This model does not also support HomeKit – – that one costs more.
All three of these are cloud cloud integrations. People have reported that it can take a couple of hours before the devices show up in the smartthings app after you link the accounts.
Meross has added a $5 off coupon for their 2 pack of 16A HomeKit-compatible mini smart plugs (Model MSS110HKKIT), making them 2 for $20. These should work with the smartthings integration as well. Make sure you check the Meross app for each device individually to see if they need a firmware update: they will not work with third party integrations if they are not up-to-date.
Remember to check the coupon box on the page before purchasing. Also, you can use the coupon more than once, but only on the first item put into your shopping cart for each order. So you have to put in multiple orders if you want more than one two-pack.