My sheep hunt last November we stayed at a place called Quality Inn, which was off exit 36 in Yakima. It was about the cheapest of anything else I could find, I think it was around $55/night. I was told later by Ric that it's not the safest part of the city. But I liked it because it was right off the freeway and the rooms had outside doors to the rooms so we could park just outside of our room and not have to carry things far.
It wasn't the fanciest motel, but it served the purpose. I don't like to spend much money on a motel room when all that's needed is a bed to sleep in for the night.
You could probably stay in Ellensburg as well.
