Vernazza is filled with inexpensive affita camere (rental rooms) with varying levels of quality and cleanliness. If you prefer not to gamble with your lodging while in the Cinque Terre, check out Gian Battista's 4 rooms near the tower just off Piazza Marconi, the main square on the breakwater.
Gian Battista's rooms are clean, offer wonderful amenities, have Internet access that works (I am typing this from room #20), and a few have incredible views. You can also take advantage of the rooftop terrace for sunning or simply enjoy an evening glass of vino as the sun sets over the Mediterranean.
The rooms are more expensive than most Vernazza B&B offerings, but the peace and tranquility are worth it. Rooms #26 and #31 are stunning; Rooms #19 & #20 are smaller but less expensive. Breakfast is included, which you take at the nearby Bar Ananasso, Burgus, or the Blue Marlin Bar (my favorite).
Upon arrival, Gian Battista (or a family member) will meet you at the train station, then escort you to your room up a fair number of stairs (be ready for it). Call or text him to arrange a time to meet. Gian Battista will help you bring your bag up to the room if it's not huge (pack light in the Cinque Terre or you'll regret it). You can pay on departure.