Are you suggesting that Flippiness should use those services or are you saying that a person can use those services for free without paying?
If latter, yes we could use those but we don't know how frequently they update their prices. If there is a mismatch between their prices and source prices, our data will be inaccurate. We get prices continuously in a cycle for all books that we have (almost a Million). This ensures we remove stale records.
If you meant Former, the issue is a person can't manually check prices for a lot of books every day. Even if they did it will cost them more timewise than our membership dues.
If latter, yes we could use those but we don't know how frequently they update their prices. If there is a mismatch between their prices and source prices, our data will be inaccurate. We get prices continuously in a cycle for all books that we have (almost a Million). This ensures we remove stale records.
If you meant Former, the issue is a person can't manually check prices for a lot of books every day. Even if they did it will cost them more timewise than our membership dues.