With a population of around 700,000, Dushanbe might not be terribly big, but it is rather spread out, so there is an extensive if erratic public transport system. It's built in a valley, so many parts can be accessed using the city's trolleybus system that runs the length of the valley. This is the cheapest way to get around, a ride of any distance will cost you 10-20 dirhams (3 pence max). 

To get around in the south of the town, where the valley spreads out, you will need to take a marshruka. These are found all over central Asia, running along set numbered routes. These will take you closer to your destination more quickly, but not necessarily more comfortably. Rush hour in the mornings will often lead to maybe fifteen or sixteen people in a nine-seater minibus. The driving and traffic are similar in their intensity. Depending on how far you're going, a marshruka ride will cost between one and five somoni (14-70 pence).

If you are in the north of the city, in embassy territory, the valley narrows, so most places are quite easy to get to  - you can walk the scenic Rudaki avenue to get to the city centre.