It depends what era you are looking for and how much you want to pay. If you want 90s Hooker pieces then they can be found on eBay with ease. 50s, 60s and 70s piece are much rarer and will probably cost you more.
To clarify what Paul posted, we have a member who was John Lee Hooker's personal assistant, and she has a lot of his genuine stuff. Her prices are definitely reasonable and well under what others ask.