I am looking to find out how much a full dionostic test should cost me

Well my service engine light cam on a few days show an I took it to advance auto an they put it on there computer thing an they told me that there are me any codes showing up an they recommend that I take it in an have a full dionostic check run on it

if that light is on and advance checked it and no codes were stored,then that may be a service engine/maintenance light instead of the check engine light.look in your owners manual and see what each symbol means.the light that's on may only mean it's time to change your oil?very important to read your owners manual,and keep it somewhere,so it doesn't get lost.don't pay anyone anything until you read your owners manual.you may not need that done.