Who won't thank you for a full wallet? Your employees certainly will! So, don't forget your employees when you think about promotional products. If you want to show your employees you care, choose a unique promotional product they can use and will remember.
If you're running a sales contest, make one of the prizes an imprinted wallet they can use to hold all the cash they make during the contest! Wallets are always useful, and your employees will thank you for giving them something to fill up and use again and again.