I'm an old fart, and I've bought a lot of gifts for gals over the years.
This works.
Buy a picnic basket: The old fashioned kind with two lids like in the movies.
Get a red/white checkerboard tablecloth...like in the movies.
Bottles of wine, two wine glasses, some cheese and goodies. Candles.
She'll think you spent ages on a theme gift just for her. Chicks LOVE this! I used to have at least two or three sets like this in my apartment during my twenties (I was a dating fiend then!). Get em on sale, and you won't have to spend a dime at Christmas.
Remember girls think they are Psychic, and they will over analyze your gift. To a gal, gift giving is a test of your inner psyche. Give her every reason to think it took you at least a month of pre-planning to get this gift.
The coupon idea is good, but NOT for Christmas. She wants a tangible thing to hold in her hand. Coupons are good as an addition to you gift at Valentines day or some 3-6 month bogus anniversary.
Remember you will be graded on this. If she asks, it took you a month of searching to find the right basket (cause you a guy, actually spending time shopping for a gal is impressive).
Jewelry in my mind is bad. ONLY if you are going to marry her. Its a substitute for...commitment!
Frankly: is a very chick thing. To me, a glass/zirconium jewel looks like the real thing, so its just as good. Its for looks anyways. If no one can tell the difference, whats the big deal? A chick is looking for a way to judge how you value your relationship, and the price tag is a perfect way to do that.
Fear, oh mortal man. Jewelry is bad!