The people in commercials are NOT a good indicator of what you will look like after following the workouts or equipment that they are trying to sell. Please do not base your choice of exercise on this.
Regarding finding them on the internet, beware. There are counterfeits out there that have injured people when some of the connections gave way. I bought mine direct from TRX for $300 bucks. About the cost of 5 months membership at the closest gym to me. I had found one on Craigslist for less than half of that but after comparing the pictures in the ad to the pictures on the TRX site, it looked to be bogus.
Like my dad used to say, "Quality is like buying oats. If you want fresh, clean oats, you have to be willing to pay the price. If you can settle for oats that have already been through the horse, that comes a lot cheaper".
I would rather pay for quality any day and know that I have something that will last me for many years.
AKA: Texas Grok
TRX is another great tool to add to your work out regime and if you're currently just getting back into a work out program I would recommend it because its a great way to add assistance to full range of motion body weight movements.
That being said there are some cons with the TRX system as well. A lot of people will tend to rely on the TRX too much and end up having to "relearn" position and posture once they have graduated to a body weight program or into using free weights. Personally I like to use it for clients who need rehabilitation or are beginners because it allows for more natural movement than machines as well as added stability when in challenging positions.
Yes there are some very challenging movements that can be made with the TRX but once you're able to do those movements IMO its best to step away from the suspension trainer and work on body weight exercises so you can also work balance and spacial awareness.