I have made a few cutting boards and all you need to finish them with is butcherbock conditioner. It’s cheap and effective. You will need to re apply occasionally.
Edit: this is the stuff I use. https://www.amazon.com/gp/aw/d/B001ESTA30/ref=mp_s_a_1_1?ie=UTF8&qid=1476097252&sr=8-1&pi=SY200_QL40&keywords=butcher+block+conditioner&dpPl=1&dpID=41GzByt%2B7CL&ref=plSrch
A little goes a long way.