Nepal has made the visa and customs process easier and straightforward for most nationalities. Moreover, one doesn't need to pay any visa fee if they hold the passport of a member state of the South Asian Association for Regional Cooperation (SAARC) for 30 days. You can get a visa on arrival at the Tribhuvan International Airport in Kathmandu, and all land borders are open to foreigners. You can pay fees in foreign currency. 

These are the present visa fees:

On Arrival Visa Fee at Entry Points

15 Days – 30 USD

30 Days – 50 USD

90 Days – 125 USD

About Nepal Visa

Nepal extends visas to almost all nation citizens around the world. Indian nationals do not need access to enter Nepal. The Nepalese Embassies or Consulates out of the country and the immigration offices provide a sixty days visa upon the required documents, presentation of a valid passport, two passport size photos, and a payment of the equivalent of US$ 25 Single Entry for 15 days Visa, US$ 40 single entry visa for 40 days and US$100 single entry visa single entry for 90 days visa. Children below ten years are free from paying the Visa Fee.

Tourist visa

The Immigration Officer of the entry point or the mission for fifteen days, thirty days, and ninety days entry visa in a visa year.

The Director-General for renewal the validity of the visa and regularize the tourist who has already entered Nepal by obtaining an entry visa.

But the immigration officer of the entry point may regularize the visa for fifteen days at departure time if the totals stay period in a visa year does not exceed 150 days.

For more details, please visit this link. Nepal visa