I was in a similar situation as yourself, clubs that were way off, and wanting to improve, I decided to go ahead with the purchase. I did notice that once I had the right length and lie for me, that I was hitting the ball much straighter with the test club.
I just had myself fitted for new Ping irons and fairway woods, and the way I went about it was to determine, both through reviews and word of mouth, determine approximately the brand and style of clubs I wanted. Once I had decided on that, I spoke to a few club pros and other golfers I knew to get references for the clubfitter, and from that spoke to a couple to determine what I wanted. Once I had the clubfitter I wanted selected, I asked them for a rough idea of the cost of the clubs, and compared them to the box stores, online etc. What I found was, especially for Ping, that the price for new clubs did not really vary at all.
Once that was done, I booked the appointment, had the fitting done, which I was very impressed with, and ordered the clubs. I ordered a new set of Ping G25 irons, a G25 3 and 5 wood, and a Ping Gorge wedge, and am just waiting for delivery.
This was my experience anyway, so I hope it helps.