Most golf courses will have clubs available for rent on a per round basis. Although rates can vary by course, average rates are £30 to £55 / €30 to €50 per round and £40 to £60 / €45 to €75 per day.
Pioneer Golf can request and reserve clubs on your behalf.
Auchterlonies, a golf shop in St. Andrews that is only a pitching wedge from the Old Course, rents clubs (2-4 Golf Place, 44 01334 473 253, https://www.auchterlonies.com/). Sets are available for approximately £30-40 per person per day. The vast majority of rental sets are TaylorMade clubs.