Travel costs to Iran are a function of two variables:
1- The exchange rate of the Iranian Rial (IRR) against foreign currencies such as the US dollar and the Euro
2- The rate of inflation growth in Iran
This means that the lower the Iranian Rial against foreign currencies, the lower the cost of travel within Iran for foreign tourists.
On the other hand, the higher the domestic inflation in Iran, the higher the overall costs (travel or living) in Iran will be.
In 2020, Iran saw a sharp fall in the value of the rial against foreign currencies. A brief look at the statistics shows the value of the rial against foreign currencies.
In 2011, you could exchange one Euro for 15,000 rials. In 2014, you could exchange one Euro for 42,000 Rials, and now in 2020, you can earn about 300,000 Rials for each Euro. Of course, due to sanctions, government policy, inflation and the floating exchange rate, the parity of the rial against other currencies is changing daily, but the result of these changes is a decrease in the IRR exchange rate against foreign currencies.
Conclusion: Now the cost of travel to Iran for foreign tourists is significantly lower than in previous years. In fact, Iran is nowadays among the cheapest countries to travel to. This situation will continue as long as price inflation in Iran significantly increases costs in this country. Therefore, the coming years in terms of prices are the best years for foreign tourists to travel to Iran.