The fastest option to get to Santa Marta will be a bus from Berlinastur
There are different options to go from Cartagena to Santa Marta, however Berlinastur seems to be the best option, because they are closer than the official bus terminal far outside the city. Also there are services that offer to pick you up at your hotel, but it’s possible that these busses have to pick up people from more hotels all over the city.
Berlinastur Calle 46B #3-80
If you take a taxi tell the driver to go to estacion Berlinas-Marbella. If he doesn’t understand, tell him ‘cerca el cabrero, deretsya a el hotel cabreromar, calle 46b con tercero’ (kaye kwarente-says b)
Places to stay in Santa Marta Colombia
I liked the hostel ‘La Villana Boutique hostel’ with a shared jacuzzi, and a little bar to meet other travellers easily. The hostel is located very central, close to the sea with good vibes. Shared rooms start at $5,- , and private rooms for two persons at $25,-
For something more private i recommend Kayros hostel. These lovely women offer a private double room en suite, with a shared kitchen. The downside is that it is in ‘Calle 10c’. Exactly the border between the tourist area, and the prostitution / addicts zone, BUT the price of around $10,-/15,- compensates this.