The seller is listing an unusually large number of the same exact bag. This is a red flag because there are websites where you can purchase good-quality replicas, and I have seen these replicas listed on eBay claiming to be authentic.
Note that replicas are usually made of fabric, as leather is more expensive and therefore all-leather bags are less likely to be fake. (However, I have seen fake Coach bags made of all-leather. The all-leather fakes are usually very easy to spot – i.e. the quality of the leather is VERY poor, the fixtures are all wrong, etc.)
To have a taste of some of the Coach counterfeit you could find on the market, here are some photos of Coach replica handbags.
[...] Signature fabric 2. The stitching 3. The bag does not look like any other bag 4. Replicas 5. Photos quality 6. Authenticity mention 7. Credo Patch 8. Fixtures 9. Zippers 10. [...]