e-bay stores with their own sites and are authorized Titleist dealers will guarantee the authenticity. Not limited to 2nd Swing and Global Golf but as examples. "New" sets shipped from China are always counterfeit. Some small number of sellers may be unloading "hot" clubs stolen off of golfers, not necessarily their own personal clubs. In-between, there are legitimate resellers, but hard to identify or know if they can authenticate clubs.

Local retailers/pro shops may either stock used sets or with a pro shop, connect you with someone with a recent upgrade and willing to sell their prior set.

Global Golf and 2nd Swing are about the best for selection on used and older model clubs also when ordering from Ebay look for sellers that have 99% -100% rating also look in the description of the item some of the sellers guaranty authenticity of the clubs..it just takes a little time to research what model and what price you want to pay hope this helps...

Try SecondSwing.com; GlobalGolf.com or 3Balls.com These are the most reputable ones I am aware of. Good luck

secondswing.com I bought a used Scotty Cameron on their website. Very reputable site as far as I know.

Look here...

valueguide.pga.com/