Aussie and Mauritian traveling to Nepal.

Hi, good evening.

Can anybody tell me if a Mauritian Citizen and Australian Citizen need a visa to visit Nepal as tourists?
I believe it's just a visa on arrival and you have the choice between 15 days, 30 days or 90 day stays for different costs. This true and is it valid for both Australians and Mauritians?
Would love to go for 30 days either from India or Sri Lanka, not sure which one yet.
Can I apply in either country before arriving in Nepal, or is it much easier/better to do it when you reach the airport?

Thanks in advance for anyone who can help.
Worldtraveller.

I'm not an expert, but I do know that you can purchase visas at the airport in Kathmandu upon arrival.  However, depending on when you arrive it may be crowded and I've heard the wait can be long so it may be easier to get a visa in your home country before you leave if at all possible. 

I'm pretty sure you don't need a visa if you are an Indian citizen or a citizen of a SAARC country.  Again, I'm not an expert so you might want to look it up on the Nepal Tourism Ministry website or the Consulate of Nepal in your home country

Im a Mauritian and I am on a short term stay in nepal. Visa on for foreigners are on arrival and it costs USD 40 for one month, USD 100 for 3 months

Hope this helps