Apple 12" Intel Core M 256G SSD Macbooks

I hesitate to get back in the Mac universe, but I did buy an older Macbook with 2 GB, Office, etc. for $80 and it is nice.

How good a deal is this one, as I am too lazy to sort out the Mac models. How soon will Apple make it impossible to update the OS, as is the case with my Snow Leopard Macbook?