Stayed here once a few years ago, and it was fine. It’s not the cheapest, but it is the closest to campus. You can leave your car parked at the hotel and walk to campus:
http://doubletree3.hilton.com/en/hotels/north-carolina/doubletree-by-hilton-hotel-raleigh-brownstone-university-RDUDNDT/index.html
-or-
If I want inexpensive, I stay at LaQuinta at RDU airport, and drive 10 minutes to campus. Its newly remodeled, and offers a simple breakfast bar for free:
https://www.lq.com/en/findandbook/hotel-details.raleigh-durham-international-airport.html