As your rental periods are so flexible, I would change to a mini-calculator with a guide price, like this:
This allows you to be more succinct in designing your cards, save space and gives users the ability to get an accurate quote for their rental period, with a bit of adjusting, you could show discounts for extended rental periods in the quote.
I see some of things in your explanation:
1 - Putting prices in a slider prevents the user from seeing all prices at the same time to make a comparison and requires to interact with the card. I think that's not what you're looking for.
2 - The landscape format space intended for the image is too long, twice the height, is it necessary this proportion/size ...
Madalina, a general minimum width for buttons, as stated in the Material Design Guidelines, is important, because it ensures that all buttons are reasonably easy to click or tap even for very short labels such as OK. Think "Fitts's Law."
And while same-width buttons may look more aesthetically pleasing, I've yet to see research that shows any usability ...