Hellobee Boards

I have a pokemon obsessed 6 year old!

Pokemon decks are good gifts, they're typically in the $13-18 range depending on which you choose.
https://smile.amazon.com/Pokemon-TCG-Guardians-Featuring-Holographic/dp/B071Z6FTLR/ref=sr_1_5?s=toys-and-games&ie=UTF8&qid=1541434829&sr=1-5&keywords=pokemon+deck&dpID=61csMJb5RbL&preST=_SY300_QL70_&dpSrc=srch

We also have this game that my son thinks is very fun. It's like 20 questions but it's trying to determine which pokemon you picked from the book.
https://smile.amazon.com/dp/B07CRYP9SG/ref=twister_B07H3KP47G?_encoding=UTF8&psc=1

MegaConstrux are lego like toys that have lots of really fun pokemon sets as well. Unfortunately, they're not compatible with legos.

I've combined one of those decks with a pokemon book for several birthday parties this year, which usually equals a good ~$20 gift.

Pokemon Encyclopedia
https://www.amazon.co.uk/gp/product/1408349957/ref=ox_sc_act_title_1?smid=A3P5ROKL5A1OLE&psc=1

They had some pretty cool Pokemon tees at H&M

My son has a couple of binders to organize his cards, I imagine it's the same type of thing you would get for organizing baseball cards. Luckily, the Pokemon phase is over for him, but I had thought about buying Pokemon PJs back when he was obsessed.