and / or Shimano Tiagra 10 speed
fair amount of Sora and Tiagra NOS and new/takeoff stuff avail (at reasonable prices)
Tiagra 10 speed will provide the option to go hydraulic disc if that’s your thing - but that could also bump the cost up and above ‘inexpensive’
Unless you already have 4700 Tiagra (the only current version of Tiagra available), would stay well clear of it, it's an orphan groupset soon to be discontinued, with no real compatibility out of it's own groupset.