I'm just curious what an Advanced Reading Copy signed by Robert Jordan is worth?

The nature of a collectible is that it's worth whatever you can get someone to pay for it.

 

Also, you should tell us which book.

Knowing the book always helps! =P

 

Eye of the World 

Signed versions, I think those are first editions.

Most likely place to find them would be through used book sellers.

Price/Prices might vary from seller to seller.

 

Currently between $800-$1,200. Who knows if the series is a big hit

Nothing like chiming in a decade later lol