Here's a breakdown of the best hotel booking apps for finding cheap prices in San Francisco, CA:

Google Hotels aggregates rates from dozens of booking platforms simultaneously, so you see the lowest price across all sources in one search. It's free, no account needed, and shows price history graphs so you know if a deal is genuinely good.

Hopper is one of the most popular apps specifically for deal-hunting. It uses AI to predict when prices will drop and sends you alerts. It also has a "Price Freeze" feature to lock in a rate. Great for SF where hotel prices fluctuate a lot.

Part of the same company. Hotels.com offers a loyalty rewards program (roughly 1 night free per 10 nights booked), which adds up fast. Expedia bundles hotel + flight for extra savings.

Best if you're booking last-minute (same day or within a few days). SF hotels often drop prices significantly on HotelTonight to fill empty rooms.

One of the largest inventories globally. Frequently has member discounts (free to join), and their "Genius" loyalty tier unlocks 10–15% off many SF properties.

Often has the lowest raw prices on SF hotels, especially for budget and mid-range options. Worth comparing against Booking.com.

Bottom line: Start with Google Hotels to compare all prices at once, then book through whichever platform has the best rate — often Agoda or Booking.com for SF budget stays. Use Hopper if your dates are flexible and you want to wait for a price drop.