Its actually 13 inch with 4gb ram
Well, the "classic" 13" MacBook Pro is still available, hasn't changed much since late 2011 (I think it had a minor processor bump) and costs about $1300 new for the i7/4GB/1TB config, so make your own judgement.
Not such a good deal as the 8GB/15" would have been though, and if the seller initially told you that's what it was, walk away!
These were the last MacBooks with user-upgradeable hard drive and memory, so you can easily add third-party RAM and a SSD (recommended) which is good. You can also swap out the DVD drive for a second hard drive, so you can have a fast SSD as your system disc and a big HD for storing bulky data.
Screen is nothing to write home about, and actually slightly lower res than the 13" Macbook Air but perfectly OK.
Main downsides: only USB 2.0 (no USB 3), and only a single Thunderbolt port which is also your only way of connecting an external display: this can limit the usefulness of cheaper Thunderbolt disc drives etc. that don't have a through connector (not so bad if you don't need an external display).