Cartagena has become an extremely trendy destination in recent years, partly because the whole country had been considered a no-go zone due to security issues in the decades prior. Now things have changed, and budget travelers in particular are flocking to Colombia in general and Cartagena in particular.
In addition to the lovely scenery and friendly people, Cartagena is still quite cheap by international standards. It’s more along the lines of Panama City or San Jose as compared to Lima or Buenos Aires in South America.
Hotels are quite cheap, even during the high season, so this is a very popular destination for sunseekers during the North American winter.
Most attractions are free or cheap, and food and drinks can be found at real budget prices as long as you stick more to the things the locals are eating rather than meals and beverages from the fancy hotel restaurants.