There are several succulents that resemble each other, especially when small like this one. I am leaning towards either Graptopetalum, or Pachyphytum - you can see one of those on the page about succulent plants miscellaneous. The leaf shape is most like Graptopetalum 'Fred Ives' which is a very popular and easy to grow variety.
You will need to look at the guidelines on the page about succulent care to grow them successfully - they do not like organic type soil, which it looks as though this one is in right now.