Well, I've never had a problem with PM'ing and using a coupon with Staples.com when I call them. I've done it with the Antec 1080B case/PS, natural pro keyboard (although I didn't like the total when she finished, so I decided not to go through with it), and this monitor.
Hell, CSR won't match EMS computing anymore (cheapest on 955DF I found), so HE even asked if I wanted to PM somewhere else!!! Even though TechSavings.com appears to be the same people, Staples doesn't seem to know that and it was only a few dollars more at most on that site (search on pricegrabber). Told him I had a $40 off $200 code, and he said, no problem.
Maybe I've just been lucky, but I've never had any difficulty doing this.