I need to know if I can save money on a digital camera in duty free shops before flying to the USA..?

i AM LOOKING TO SPEND ON A DIGITAL SLR CAMERA JUST BEFORE FLYING TO USA NEXT YEAR

Don't do it.
1. Duty free shops are NOT cheap for anything except boose or cigarettes.
2. Buying in the U.S. is risky as the majority of manufacturer's do not supply international warranties.
3. And the most important reason.
If you're planning to take photo's with your new camera whilst you're away.
Buy before you go in order to allow yourself time to familiarise yourself with your new camera.Practice at home first when any mishaps won't matter so much.(You can always go back down the road to retake the shot that didn't turn out as you'd have liked), but you'll only get one chance to record this trip to the U.S.

yes

YES you will save yourself a good bit of cash buying a camera at the duty free BUT you will also get a good deal bu buying it in the USA

I find that the Duty free shops aren't as cheap as you might think and the range of products is limited.
You can probably get a better ( or at least as good deal) on the specialist internet sites (or through e-Bay).
Remember that the exchange rate with the US is also in in our favour so you may find that it would be cheaper there - but you do have the downside of the power plug for the battery adapter being a US plug.
Also, some of the warranties are restricted to the US if purchased there.
It's never clear cut.

Yes anything you buy in a duty free shop in UK will save you money.

Have to say I was very disappointed with duty free last time I travelled - cheaper than retail mrp but with no deals and a limited ramge. Digital cameras are considerably cheaper online - try www.pixmania.co.uk. I also think that you would get a good deal in the States, especially as the exchange rate is so good at the moment.

If it were an inexpensive camera, I'd advise you to just buy it now and start taking pictures. For expensive items however, such as the dSLR you want, buy the camera in the USA.
Look up some local prices for the camera(s) you're interested in. Then compare those to prices in the USA:
http://www.beachcamera.com
http://www.ritzcamera.com (stores everywhere)
http://www.bhphotovideo.com (very large store in New York)
Odds are, the price difference is enough to buy a converter for the battery charger... and also substantially subsidize your trip ;-)
Duty free stores don't charge sales tax, but their profit margin is so high that you usually don't save any money vs. normal shops. And as previously mentioned, they tend to have a very small selection.
Regarding the warranty, good point. You'll have time to test the camera during you're visit, but if things go wrong back home you probably won't be covered. It's a risk that I would be willing to take (and have taken with some of my Nikon gear). If the camera works fine the first day, there's a 99.9% chance that it will continue to work fine until after the warranty expires.

Don't bother with duty-frees for anything except tobacco and booze. You'll do better in the High Street or the internet..Check some prices on the shops before you get to the airport and then see what ridiculous prices the duty-free shops charge.Complete rip-off. Stuff is very cheap in USA,but be careful about warranty agreements. Getting an adaptor for UK mains to fit USA stuff is no prob. Very cheap and you can buy them anywhere. I bought a 1Gb SD card from USA on the Net for half the price I could get it here,and no customs duty to pay. They don't bother under a hundred pounds or so value. of goods. Not worth their while.