Is my math right?

I have a lot of old automobile brochures. I thought about selling on Amazon but see if this is correct.

We’ll say I sell a item for $10, fee’s are: $1 to sell the item $1.50 for Amazon 15% finders fee $1.80 for being in the Media category.

So already $4.30 of the $10 is going to Amazon?? Before shipping is settled or even a thought of taxes.