Amazon Ads Front Page Placement

I am setting up my product to sell on Amazon and looking at sponsored ads. I decided to do this yesterday and got around 500 impressions in 24 hours. However I noticed that of these impression only 22 were front page.

I wanted to look into adding a more definitive approach to getting into the front page but got confused to when I stated 10% front page placement it was telling me it could cost 100 dollars for a 1 dollar bid. I am wondering if someone can explain this to me and how it would work.

I set my ad campaign to not exceed 25 dollars, and I am wondering if one ppc would exhaust my budget.

Thanks,