CPC
CPC (cost per click) divides the fee by tracked clicks. It sits between attention (CPM) and outcome (CPA) in usefulness: clicks show intent but not purchase. Creator campaigns need unique links or codes for CPC to be measurable at all, which is one reason per-creator tracking belongs in every brief.
Worked example
A £400 story sequence driving 500 link taps cost £0.80 per click.
Full context in the guides, or measure it yourself with the free tools.