Zuidtangent bus question

I leave today and have another question about the Zuidtangent bus from Schiphol to Haarlem. Rick says the fare is "about" 5.60 euros. I have a five euro bill, and I was sure I had some euro coins. Turns out, I don't. I assume if I give the driver 10 euros, he can't make change, right? I should stop at the grocery store and buy a bottle of water to get change, yes? Thanks!