The free version
What you can see after dark without a ticket at all
Three street vantage points, all lit, all free, all worth the twenty-minute walk.
The Colosseum sits in the open, on a busy junction, with public streets on every side. After dark it is lit, and none of that costs anything.
From the rise towards the Arch of Constantine. The classic angle: the arch in the foreground, the amphitheatre behind it, both lit. This is the photograph most visitors keep, and it is taken from a pavement.
From the terrace above the Roman Forum on Via del Fori Imperiali. Looking back along the excavations with the Colosseum closing the view at the end.
From the Colle Oppio side. The park on the slope opposite gives you the whole oval from slightly above, which is the only free vantage point that shows its shape.
A daytime tour and an evening walk around the outside is, for most visitors, the best value combination available — the interior explained by a guide when it is open, and the building itself at the hour it looks best. Tours start at $43 and the walk is free.