As far as I can see, the `lo` is simply being used expressively to emphasize the speaker's point (and it refers to *todo en la vida*, as another answerer mentioned).

The meaning is almost the same as:
> El dinero no es todo en la vida.

*Money isn't everything in life.*

The extra `lo` gives a feeling similar to this English phrase:
> Money - it's not everything in life.

or
> Money is *not* everything in life.

That, or it could simply be a typo, assumed it's written. The writer may have started with *El dinero no lo es* and changed his/her mind but forgot to delete the `lo`. This is admittedly a long shot, and I think my first suspicion is closer to the truth.