Avoiding run ons with a comma or a period

Here's an example of a run on sentence of and how I fixed it.

Ex:

Run on-
My mom says she was going to bake cake but she didn't because we didn't have all the ingredients.

Fixed-

My mom says she was going to bake cake but, she didn't have all of the ingredients.

A, this way you know that there’s a less of a chance of it having biased information or edited by other people-making false information