When searching online for store coupons, do you type "coupon" or "coupons"?

I'm just trying to get a consensus from those of you that use Google or other search engines to find coupons and/or coupon codes for certain stores. Do you type in "store name coupon" (singular) or "store name coupons" (plural)

The reason I ask is because I feel that the natural thing to type as a consumer would be the plural form. For example, Target coupons or Burger King coupons, rather than the singular form (Target coupon, Burger King coupon), but I was doing some keyword research today because I want to start a coupon site for a certain store, and Google's KW tool is telling me that more people type in the singular form of "store name coupon" rather than the plural "coupons" and it just doesn't seem right.

The numbers are way different too - the singular form of the phrase gets 1,300 searches per month while the plural only gets around 200 according to Google's KW tool. This is on exact match too which is all I go by.

I then double checked my results by using Wordtracker's tool, and they are reporting much different results with the plural forms getting more searches.

I know keyword tools can be way off so that's why I'm asking you all. So when browsing the web as a consumer and not an IMer, which way would you do the search? Would it depend at all on the store you were searching for, or would you always do it the same no matter what?

On a related note, which KW tool do you find to be more accurate, Wordtracker or Google's tool?