CrowVerdict pass
COLOSSEUM
Yes, and the cheapest ticket is the one you want. €18 covers the Colosseum, the Roman Forum and the Palatine for 24 hours. The €24 tiers buy a floor, not a better day.
Verdict
Is the Colosseum worth it?
Yes. The €18 one.

The quick take
Read the bill, check what your admission ticket includes, and leave time for the ruins. Airport train fares and fixed taxi fares are different options. The Vatican's Sunday schedule needs a look before you plan around it.
Quick practical notes

CrowVerdict pass
Yes, and the cheapest ticket is the one you want. €18 covers the Colosseum, the Roman Forum and the Palatine for 24 hours. The €24 tiers buy a floor, not a better day.
Verdict
Is the Colosseum worth it?
Yes. The €18 one.
Preview pass · not a ticket or reservation · № 0047
Explore Rome
Practical tips
It covers the Colosseum, the Roman Forum and the Palatine for 24 hours. The €24 tiers only add the Arena, Underground or Attic.
Flat fare per vehicle from Fiumicino to anywhere inside the Aurelian Walls, supplements included. Ciampino is €40.
Lazio law bans additional cover charges, with a €2,500–€7,500 fine attached. Ask for it to come off.

Ask Crow the next question. It plans the trip, prices the route, and changes the day when the day changes.
Get Crow