A really easy way to insulate your home is by adding foam insulators to all the electrical outlets and switches located on the exterior walls, I do the interior as well as I have an old house. The foam insulators cost around 4.99 per packet plus tax and one pack is never enough. I had a revelation why not use the styrofoam trays that food comes in, just cut out and use instead, I do wish I thought of it sooner as I would have saved a bundle. Use the plate as a template and then cut out.
Hope this is a tip you can use.
Another useful tip – this was a mushroom tray and in my area we cannot recycle them so they have to be thrown away.
Other uses would be using the small trays for small jobs – holding screws, small disposable paint tray,