One of our forum members had asked about a cheap generator transfer switch for their home.
An external disconnect can run about 500-1000 dollars based off local electrician rates but an inexpensive option is a $40 interlock kit. You run a separate line to your generator and when you lose power the interlock kit allows you to safely disconnect from the grid.
I filmed the operation of ours in the video above.
The kits are specific for the brand of panel you have and you can find them either on Amazon or here. It is illegal in some states for homeowners to work on their own electric panel so check your local codes. If you do not have the knowledge to do this it is well worth paying an Electrician for a few hours to install it for you. Stay safe!