Is it easier to gain citizenship in Australia or in Europe & which one has the lowest cost of living?

I think that its easier in europe because if i gain brit citizenship i can live in several brit nations such as scotland, ireland, and so on with no problem whereas 4 aus i gain only citizenship to them but im not sure 4 new zealand. The cost of living im not sure of because i have to convert the brits pounds to american dollars. please help me.