Border Guards are Non-player characters who patrol the border gate between eastern Lumbridge and north-western Al Kharid, charging an entry fee of 10gp provided the player has not completed Prince Ali Rescue. Once the quest has been completed, the right click option "pay-toll-10gp" is still effective, and will not charge the fee.
They appear to be wielding a Steel halberd.
Border Guards guarding the toll-gate.