Local delivery free shipping over certain amount

ecmc17
Tourist
5 0 1

Hi guys ! 

I've got an online grocery store and I use the local delivery option. I would like to offer free delivery for orders over a certain amount but it is currently not possible on Shopify. Does someone have an idea on what to do to make it possible ? 

Thanks 

MikeTaylor
Tourist
9 1 2

We would like this too. We offer free local delivery to anyone who spends £40+ but it is available to everyone however much they spend.