The anytime goalscorer market pays if your player scores at least once — own goals usually excluded, and the bet typically needs the player to actually take the pitch to stand. Prices track three things: the team's total goal expectation, the player's share of it (penalties help enormously), and expected minutes.
The classic leak is betting on reputation: a famous striker starting on the bench, or one whose team creates little, carries a price far shorter than his real chance. Check the lineup and the team's attacking numbers before the name.
A striker taking ~30% of a team expected to score 1.6 goals has roughly a 1 − e^(−0.48) ≈ 38% anytime chance — fair odds about 2.60. Books quote him at 2.00 on name value alone; that gap is the margin you volunteer to pay.