The biggest misconception I hear from average players is they are not good enough for custom fit clubs. In fact just the opposite is true. The reason is that properly fitted clubs will reduce the severity and frequency of your bad shots. Low handicap players have sound swings and a much smaller percentage of off center hits. This is not the case with the average player.
I urge you to seek out a professionally trained club fitter who has a proven track record of knowledge, expertise and experience. A professional club fitter is what a tailor is to a suit. Properly fitted clubs can and will improve your scores.
I worked for a big box golf retail store for 4 1/2 years before opening Golf Rx. They want to sell you what's on the rack - in most cases their "Certified Fitter" has no professional training. Also keep in mind that bad specifications on todays clubs are getting in the way of you improving. Drivers and fairway clubs are too long, fairway clubs don't have enough loft, nor do long and middle irons.
Determining the correct shaft for the average player is critical in the fitting process. The total weight and swing weight must be fitted to your size, strength, downswing tempo and swing force or you cannot achieve proper swing consistency. Properly fitted shafts will result in a higher frequency of on center hits. As a result you will get the best set of clubs you have ever played with.