My visa ends on the 29th, if my work permit is canceled on that day will it entitle me to an extra week in the country? I need to stay in the country until the 13th. I was hoping that I would get one extra week from my work permit and then I would go to immigration and pay 1900 for a week on top of that. Or is it better to to just leave the country and get the extra 15 days?

You must leave the country and return for 15 day visa exempt if you want two weeks. Your extension of stay ends the day your employment ends - there is no extra week unless you apply and pay for extension of 7 days. If you are actually on a 90 day visa entry you could stay until the current permitted to stay date.

A work permit is to allow you to work here, it does not have anything to do with Immigration.

Do as Lopburi has said