I initially said Alabama, but then did some research. Of the options listed, NH had the lowest percentage of combined taxes (Alaska was the only state lower). NH has the reputation of the most Libertarian state in the US, so it would not surprise me if they are the most economically right-wing.
Tax rates are not the only issue in whether or not a state is fiscally conservative. And this question is about the average republican voter not the policy that is in place in a state.
It may not just be tax rates, but if fiscally conservative equals low taxes/spending, then I think it is a fairly good metric. I did see (at least in 2007) Texas spent the lowest per capita of any state, but is currently running a $10 billion deficit, which I'm not sure is a characteristic of a fiscal conservative.
Also, I guess I didn't understand from the question posed that the inquiry was limited to the republican voters of the state. However, since both TX and NH state legislatures are overwhelmingly Republican, to the extent those legislators accurately reflect the will of the Republican voters, I would say either NH or possibly TX would be my choice.
Well I made the mistake of thinking it was policy instead of voters. We're talking about majority Republican states, but no its not just limited to Republican voters.
But here is one. Indiana just passed statewide education vouchers. How a policy like that isn't becoming law in Texas, Alabama, etc. when they have had GOP legislatures for a while, I have no idea. But statewide education vouchers is very, very good. Plus they actually sold a highway to private investors and Daniels actually laughs that they way overpaid.
You don't see legislation like that in New Hampshire, Texas, etc. Even though I will say Texas is now one of the best legal environments for business in the country. So yeah in terms of legislation its not just tax rates.
But again this is about voters here. And New Hampshire still has a lot of Boston suburb liberals.