None other than Ray Allen himself had some jersey's pointed out to him by his friend which contained some fake autographs on the eBay marketplace. As always, please do your due diligence while purchasing any signed memorabilia, try to only purchase those that come with legit certifications and always check the serial number on the respective website before handing over any of your hard earned dough. Some of the trusted autograph certifications you can trust are PSA, BGS, JSA, TriStar, ISA Witnessed, CGC Witnessed.
"A friend of mine sent me these pictures of my jersey’s autographed and for sale online. The one thing they got right was that it’s a signed jersey but, here’s what they got wrong- I did not sign it. These signatures are NOT mine, so if you are an autograph collector make sure that you only buy your memorabilia from reputable sources that give you a certification that the autograph is authentic. It is a real shame that people are taking advantage of people in this way; most autograph seekers are real fans, they deserve better! #fakes" - Ray Allen via Instagram