You don't have to supply (i.e. buy) your own hardware, but you might have to pay for the power supply.

On the contrary, you likely have lower commuting costs.

However, the more important aspect might be that you end up needing more space at home and the employer needs less space in the office. Working from your kitchen table is probably not the best idea in terms of ergonomics.

In my opinion this aspect gets few attention in the discussion.