Try something like this:
(price > 15000 ? price*0.092515 :
(price > 10000 ? price*0.09301 :
(price > 5000 ? price*0.093505 : 0)))
So this formula is saying "If it's greater than 15,000 then give me X amount; if it's only greater than 10,000 (but not greater than 15,000) then give me Y amount; and if it's only greater than 5,000 (but not greater than 10,000) then give me Z amount. If it doesn't fit any of these (aka less than $5000) give me 0.
