My husband used to purchase these expensive products to clean the microwave. They were pouches that you warmed up and then wiped down. The first time I went to clean his microwave I needed 4 of them, and the thing still wasn't clean. It wasn't that his microwave was exceptionally dirty either, it wasn't.
Now to my shame our microwave is disgusting. Things have blown up in it and it has gotten super gross. I have a great solution for cleaning the microwave, it works great and it costs pennies.
What you will need:
Pour water in your bowl and add a splash of vinegar. I also toss my rag into the bowl so it's nice and warm. Then you set it to cook for about 3 minutes, now be extra careful because it is HOT! Ring out the rag and wipe down the top, bottom, and sides of your microwave until they are nice and clean.
Super easy and super cheap!