Don't buy autographs/signatures on eBay. They are mostly fake. Here are some warning signs to look out for:
1) The identity of the buyer is hidden. This is usually done so other eBayers can't warn the potential buyer.
2) The image shown is not large enough to see the autographs. There are many sites that have images of real celebrity autographs which you should consult before making a purchase.
3) The seller does not offer proof that the autograph is real or causes delays when you contact him/her.
4) The autograph comes with a "certificate of authenticity". My Grandma could print a piece of paper and call it a certificate of authenticity.
5) If you are going to buy autographs on eBay, only buy from sellers with huge amounts of feedback who offer proof that signatures are real.
I hope this info saves someone some money.
* Not a guarantee.