Was I in the wrong to charge my client for a special paint brush ($10) that I needed to finish painting the room (please read description)?

Anonymous
I paint rooms as a side hustle. I actually got so good at it that it eventually became my main job and I quit my old job to focus on this small business.
Anyway, there was a room that required a special brush that was $10 and I charged him the brush because I do everyone’s shopping for them. I buy the paint, the suppplies and everything.
He goes down my receipt because I always show it to everyone so they can see I’m honest. He says “hey what’s this $10 brush for?” I told him “yeah I needed that brush for one of your rooms.” He said “oh I’m not paying for that.”

I said “that’s fine. I’ll deduct it from my labor cost.”

He then says “oh and I’ll need my exterior painted as well.” After he finished paying me labor and the receipt cost of supplies minus the $10 brush because I deducted it.

“I’m sorry, man. I’m not doing business with you anymore.”

“You serious. Why?” He asked.

“It’s about the $10. $10 is nothing to me but I don’t want you as my business partner from here on out.”
Was I in the wrong to charge my client for a special paint brush ($10) that I needed to finish painting the room (please read description)?
Updates
1 y
Refusing to pay for a $10 brush means he is cheap and it’s just bad for business to continue with people like this.
Was I in the wrong to charge my client for a special paint brush ($10) that I needed to finish painting the room (please read description)?
10 Opinion