Hi Jamesdecosta,
You do not have to buy anything, all you have to do is get rid of the fat that is covering the muscle. Researchers have done this experiment many times to prove it. Last year a television program called "Why It's Good For You" featured this experiment here in Australia. They took 3 males, put one on a cardio exercise regime, put one on a gym program for ab development and one on a weight loss program for 12 weeks to see who got the 6 pack first, the weight loss program was the only one that got a 6 pack. I am a Neuromuscular therapist as well as a Karate instructor (5 Black Belts - Shihan), I was undefeated full contact karate champion for 6 years until I retired,ex Boxing Champion ranked number 3 in the state in 2 divisions, played Judo at state level and I have taught karate for more than 30 years and I also have a Bachelor degree and 6 diplomas in the health area.
The reason I am telling you this is simply to show you that I have done a lot of work in this area, I am not a 5 minute expert. While I respect James.W's right to an opinion the simple truth is that everyone has a very powerful Rectus abdominis muscle that runs from the costal cartilage of the 5th-7th ribs, xyphoid process and the intervening ligaments to attach caudally (towards the feet) to the pubic crest and symphysis pubis.
This muscle flexes the thoracic and lumbar spine as well as supporting and compressing abdominal viscera, it also offers anterior support to the spinal column by stabilisation of pelvic position (decreasing lordosis).
This muscle is commonly referred to as the 6 pack and if you are in a contact sport like boxing or full contact karate you have to develop it by doing crunches to close the gap at the top to protect your solar plexus, or you get knocked unconscious.This is why all champion boxers have a 6 pack. To get their 6 pack they train off as much body fat as possible and usually enter the ring carrying about 3-5% of body fat.
For demonstrations I used to stand with my hands above my head and allow anyone to punch or kick me as hard as they could in the stomach, try this without a highly developed Rectus abdominis and you are in a lot of trouble, only elite athletes should ever attempt this. All of my black belts have a 6 pack and most of the other serious karate players also have 6 packs, and they did not use weights and apparatus to get them. I was their only trainer.
James.W I am not suggesting that gym work will not give you a 6 pack because I know it will providing you work hard enough to remove the layer of fat that covers most peoples Rectus abdominis, but you can achieve a 6 pack quicker by watching your diet and using a strenuous cardio work out. You can also save a lot of money by cutting out all junk food, eating only nutrient dense, calorie sparse food and adopting a exercise program that involves a lot of crunches and running. I am an old fellow and I still have a 6 pack.
Cheers and good luck.