Need to send a letter to Nepal, no experience, which one should be the cheapest and the fastest way, USPS, UPS, Fedex, anybody got any idea.

I have used fedex in the past and it's easy and fast. They used to charge somewhere around $50 for a letter, but that was few years ago. Don't know how much is it now. My personal recommendation is go for UPS or Fedex because I have never used USPS to send something to Nepal. Don't know much about their service internationally.

I don't recommend using USPS. USPS itself is a great service provider, fast and reliable for within the US. But the problem is that they turn your package to GPO Nepal. Once they see package coming from the US those hungry wolves employees start drooling and open your package. Once opened, even if the contents hold no value to them they'll have to throw it away or get caught. You sure know what they will do.

Disclaimer: I have no legal backing for above scenarios. This has not happened to me and is based on the experiences of other people. Please use your judgment.

If I were you, I'd use DHL or Fedex or UPS. Just my $0.02.

I did USPS and it was delivered perfect. Your receiver should be notified so he/she can go to post office frequently and have inquiry.