Another stopover at Hamad International Airport, DOHA
My expenses for the 2 weeks trip, not including the air tickets, was about SGD2500 (USD1786).
Entrance fee : 100000 rials to 300000 rials (USD2.5 - USD7.5)
Taxi fare in the city : 100000 rials to 200000 rials (USD2.5 - USD5)
Metro in Tehran : Flat rate 8000 rials one way
Lunch / Dinner : 150000 to 400000 rials per meal (USD4 - USD10)
Hope the above is of help.