A lot of times they wont give you any discount unless your coach has given you a discount card. And they are only valid during the XC season (fall to winter) where I am from.
Go to a good shop (not Dicks or Sports Authority), try them on, run in them outside the store. Don't get distracted by colors or brand. Don't wear them as you everyday shoes. Get some lightweight running/cycling socks too, you will be surprised at how much they help.
Happy running :)