Originally Posted by Gardyloo

There's no official list; the Wandering Aramean's very useful site provides a quick snapshot, but some of the data there is obsolete and/or incomplete, and all fares are quoted in USD, so exchange rate fluctuations may change "cheapest" to "less cheap" at any time. You should always confirm the price by using EF or even make a dummy booking. http://www.wandr.me/RTW_Fares.aspx/

And always remember that "cheap" origin points can become decidedly "un-cheap" once taxes and fees, especially fuel surcharges imposed by the issuing carrier, are added in. The difference can easily outweigh the "true cost" one would encounter with a higher base fare but lower taxes/fees, not to mention the cost of getting to/from the "cheap" point at the start or finish.

There are no residence restrictions. Visa and immigration exceptions, however, are another thing.