I'm looking to share a horse, my friend pays £100 per month (she can go up whenever she wants to ride), and the horse i'm looking at is £20 a week, for 3 days riding a week. Another person I know pays £15 a week in the summer and £35 a month in the winter. I also know another person who gets it free. I suppose it depends on the horse and livery situation. But I think around £40-£80 a month is a good amount, as a sharer id be happy to pay that, and im not entirely certain, but i think that covers a good part of the horses costs.