I'm wrong?
Just going to cite the exact text from the book here for the item and bold what I think is relevant.
Yeah, I did bother to read it.
Okay I think the problem here is not that the toolkit is to expensive, but rather that you and your player didn't bother to fully read the gear section.
Check out utility belt sometime, it's 25 credits, grants +1 Encumbrence threshold, and provides all the "basic tools" you need to perform a particular proffesion (such as mechanic or doctor, etc).
I read your post and then picked up the book and read it again. You are wrong.
Perhaps you should bother reading it again?
"A utility belt is a common item for those on active missions where quick access to tools and gear is a neccessity; even Imperial stormtroopers use them. Their contents will vary with their user and their planned actions; sabotage missions might have belts with explosives and security slicer chips, while a ship mechanic might have his stuffed with his favorite tools. Some belts also have weapon holsters or clips.
Utility belts increase the character's encumbrance threshold by 1."
Now I assume you took this as "just" the belt, but if that was the intent of the writer I'm not quite sure what would be the purpose of descrbing the contents of the belt, surely a player could easily figure out what to put in there themselves if it was "just" a belt.