Here's what customer support told me via chat:

Your bid will go higher on searches that are more likely to convert and lower on searches less likely to convert. Over the long haul or at the end of the month, though, we will try to make sure that your average CPC is not higher than your bid.

Your actual spend might be higher or lower. This is because, regardless of any automated bid strategy you choose. Microsoft Advertising always calculates a monthly budget and then the actual budget limit is calculated for an entire month. In the unlikely event that your campaign's spend goes over your monthly limit, Microsoft Advertising will refund the overspend at the end of the month.

I am no longer in ecommerce. My site is a web app and I am not planning on making money for a long time. So I turned on Microsoft Ads today and made each keyword 25 cents but after spending $20.00 noticed my cost per click was something like $1.25. There is no way to set a max cpc. Wow even Google is not this greedy.