Short term health insurance

I posted this in r/insurance but someone recommended I post it here as well

I currently live in Michigan and I'm losing my health insurance at the end of the month as I've recently turned 26 and can no longer be on my parent's insurance. I'm in between jobs at the moment so I need to get some temporarily. After looking at a couple different options I have some questions

I go through the market place with an option that's $300/ month, but frankly pretty shitty.

I go through a different insurance option through progressive for short term insurance at $100/month that is better protection, but would come with a tax penalty for not having the minimum required insurance.

My questions are around trying to figure out how much the tax penalty would impact me. I'm having a hard time finding info on

What is the tax penalty? Does the tax penalty vary depending on how long I'm going with out insurance? For example, will it be less since I've had insurance the first 4 months of the year and could get a job with insurance later this year? Or does that not matter? I've heard that the tax penalty is a percentage of income. Would that percentage apply for the time that I don't have insurance (which would be $0 income as I'm not working) or would it apply to the whole year (which I was working before mid March and I'm looking for a job)

I'm trying to find the most cost affective option. Option 2 in the immediate time is better as it's cheaper and better insurance, but I don't know how much that will potentially screw me over in the future.