kinger,
There's a number of bore-sighters on the market that are pretty affordable. I ended up with the magnetic Leopold model that clamps to the muzzle. The bore-arbor types are also quite good.
You didn't mention what kind of rifle you want to boresight so I'll throw this out for what it's worth. If you have a bolt-action all you'll need to do is remove the bolt, set the gun in a good steady rest, sight through the bore with your eye on a distant point and align the scope to the same point. That's about all any bore-sighter will give you as well.
Don't buy into the false claims you can depend on bore-sighters to truely sight-in your rifle. After bore-sighting, start in at 25 yds. to get on paper initally then once you have that zeroed in move out to 100 yds for final tweaking.
Jim