I already did replace a front wheel bearing on my 97 Aspire about six years ago. I needed a hydraulic press but managed to do it by using a socket the right size to hammer the bearing center down on the wheel flange tube. This wheel bearing is still working fine today on a car that sees 8000 to 10000 miles per year. I bought this car in July 2000 and it currently has 180,000 miles on it. I put Mobil one synthetic oil in it when I first bought it and it still runs like new. I do not recommend installing the front wheel bearings with a hammer. It's too tricky.
Most wheel bearings are now all-in-one with the hub. You didn't say if it's front or rear. Front, don't try, the tools will cost more than the hub assembly.
