Now, when you are a sales guy and posted in a really cold territory like Chicago, I can bet that your total cost to company is going to be less than your peers outside Chicago. The main reason for this being the extremely high cost of "good" winter wear.
Two aspects define winter wear for a sales guy - (1) must look presentable (2) must keep you alive (or warm)
Walking into top a retailer store such as JC Penny, Macy's or Sears should take care of (1) and (2), but should burn a nice deep hole in your wallet too.
Best bet would be Burlingtons that strikes a balance between (1) and (2) and leave you with a relatively low bill of USD 350-400.