I know in most of the countries, especially in Europe going by a horsecart is something special and you have to pay a lot of money to use it. Mostly, tourists use the horsecart for example here in Prague to go around, but in my country Afghanistan horsecart is used as a normal way of transportation and it is a lot cheaper than Taxi. Horsecart was used a lot in the past, but nowadays, it is not very common. It is only used by poor people while here in Prague only rich people can afford it. It is quite funny :-).
The bus station in Mazar is a few hundred meters east of the shrine, across from the university. Taxis east to Konduz leave from here (buses to Kabul seem to leave from the area just south of the shrine).
The taxi to Konduz takes 5.5 hours and one seat cost me 350 Afghanis ($7US).
From Konduz to the border the whole car cost me 400 Afghanis ($8US). It takes one and a half hours or so.
Get your passport stamped on the Afghan side of the border at the police station, which has the flag outside and the carcass of the Russian tank. After that, go 100m further on to customs, then on to the ferry landing.
Tajikistan adds 1/2 an hour.
The boat across the river costs $10US.
On the oher side once I got through the border formalities I took a taxi to the nearest town which after much negotiating cost $5. They wanted to take me the whole way to Dushanbe for $60. From this unknown town I got a taxi which was all mine for most of the way for $15. You will likely have to take a mashrutka (minibus) to the centre city.
Kam Air and Ariana seem to share the same office. It is on the street heading south from the shrine, about 100 meters down on the west side. Look for the signs.
Kabul to Mazar on a Kam Air An-24 cost me about $32US.