[LakeCleElum]

I do this a lot on motorcycle trips.......Been on the road 24 days in the past 5 weeks on 5 different trips that varied from 2 days to 10 days. Throw in a Snowmobile trip and car trip to Colorado, I've been away from home 39 nights since early March.
(Good to be home for a bit).

To answer your question: Priceline or booking.com, BUT:

I usually book at least one day out, especially in the busy summer season. I usually stay at a Best Western and they claim best price is on their website. I will search Best Western over a large area and find the price can vary quite a bit between 3 or 4 BW's. Depends on how close to major city, national park or major freeway. I saved $40 once in Kansas by coming from the south on nice 2 lane state highways and staying about 30 miles off the interstate. Example: stay in Wall, SD rather than Rapid City and cut the price in half.

I usually have internet when I book and use my search engine starting with something like: "hotels in Twin Falls, ID".....This will give you a map, phone number and basic price. If calling, I say: I qualify for Gov't rate, Aarp, and AAA, what is your price?"