Garage door automation questions

I am looking to purchase a garage door opener that works with my lift master garage door. I am confused on the options you include for purchase. Do I need to purchase the gateway, control panel and garage universal remote controller? It appears maybe just one or the other (821LM or 828LM and 888LM) but I’m having a hard time figuring out the differences and what exactly I need?

If you already have the actual garage door opener, and it is a compatible module, then just get the liftmaster 821LM…$79 new

If you have home security/home automation already (via, all you need is the empower garage door control which with SuretyCAM is free for Interactive Gold ($27/month, no contract). IF on the other hand, you have no system at all, you can use the MyQ service, which is free (I think?)

It comes with the door sensor, the WiFi hub

Verify yours is 1993 or newer, and Chamberlain/Liftmaster/Craftsman -310, 315, 390, 433.30, 433.92, 434.54 MHz

The 821LM is used with a large list of non-Liftmaster overhead openers that have a compatible frequency and wireless control method.

The 828LM is used with MyQ compatible Overhead controllers (Chamberlain, Liftmaster, Craftsman).

The 888LM Wall button is a retrofit for Liftmaster Overhead Controllers that did not come with MyQ control button and works in conjunction with the 828LM.

The most commonly used component is the 821LM kit. See the compatibility list attached below.

MyQ-Garage-Garage-Door-Opener-Compatibility-List-040414-2.pdf (434 KB)