What would be the economic impact of the "fair tax" plan? So I read about an interesting proposal about completely replacing income tax with a heavy national sales tax of about 30% (23% inclusive to compare to income tax).

I was thinking about what the impact of this would be. On one end, income goes up both because people would want to work more and they get to keep everything they earn.

On the other end, prices go up because of the sales tax. I was also learning that spending is crucial for short term economic growth, so that may hurt. But does the laffer curve apply to sales tax as well? People may buy more frequently if it went down, increasing tax revenue. I know the laffer curve is unreliable, but it was just a thought.

Is this thinking process correct, or would the fair tax be a complete disaster? I apologize I just got interested in economics so I don't know much.
Well, one advantage to a sales tax is that it affects everyone (even those who don't pay income taxes). However, some people may see that same fact as a problem. This problem lies in analysis of the equity of the tax. When we consider every single person being taxed 30% on everything they buy, we need to think about how that affects different income groups. Lower income groups spend a much larger portion of their income on consumption, which means that they will be taxed relatively much more heavily than high income groups. This fact alone is enough to discourage this sort of action because the government tries to encourage saving in the lower income groups (so they can move up to higher income levels). This is one large reason why a tax like this may not be as fair as the name makes it seem.

Another piece of information that must be considered is the incidence of the tax. As we know, the incidence of a sales tax depends upon the relative own-price elasticities of supply and demand. This means that in a market with very inelastic demand (such as cigarettes or oil), the buyer is paying most of the tax whereas in a market with elastic demand the sellers would pay most of the tax. This fact would make it so that different industries would end up paying a different amount of the sales tax compared to one-another. For example, an oil company would end up paying much less of the percentage of the tax than a company making a selfie stick. This, again, seems to be unfair.