Anyone have experience with Radio ads sales cost
 

I am looking into buying some radio ads for a mainstream biz that I own and was wondering if there was a resource site of avg costs. I know it is a request that is probably hard to fill but what I am after is an idea of if the price the station is quoting me is high middle or normal. Yes I also know that demo are taken into consideration and no 2 stations charge the same.

Any help would be great.