Here's the math. $150,000 average - $44,000 for income taxes. Subtract another minimum of $3k to $4k per month for living expenses, given he was in Hawaii.
Snowden likely couldn't have saved more than $35k to $50k per year.
It would have taken him a decade or more to save the kind of funds required to both buy citizenship and live on it.
Cost of living in Dominica (2) is between 40-60% cheaper than in Honolulu. Working as a telecommuting freelancer I think he would be fine.
1: http://www.isla-offshore.com/services/citizenship-dominica/
That said, yeah, probably not enough to retire on.
http://edition.cnn.com/2013/06/28/business/world-overlooked-...
I'm sure there are other places that are a lot cheaper.
1: http://www.isla-offshore.com/services/citizenship-dominica/
If here were willing to wait 5 years to see if the Obama administration would make things better, he probably could have afforded to wait another few years. (Though one mitigating factor is the time limit after obtaining the documents and getting found out)