Answer
A combined ticket for the museums of Colonia del Sacramento costs 150 pesos, about $4. This is a convenient option for those who want to see several small exhibitions in the historic center in one day.
This ticket is especially useful because Colonia's museums are compact and close to the main sights of the old town. You can combine them with Plaza Mayor, the Street of Sighs, the ruins, the basilica, and a walk by the water.
When planning, it is important to remember that the ticket price does not create more time. If you have limited time or some museums are closed, it is better to choose two or three exhibitions and leave time for Colonia's atmosphere than to try to see everything. This way, the ticket remains useful, but the itinerary does not turn into a race from door to door.