@ican711nm,
First of all, I am no expert on this, nor am I the one to ask necessarily about the details. I am tentatively, I say tentatively, in favor of the concept, based on hearing people talk about it, such as Neal Boortz, and his Fair Tax Book. I have read columns about this, plus I have heard Neal discuss this on radio at some length. I admit I have not read his book. I have only a general philosophy about the concept, but I would not know just exactly the details I would favor until I had studied the idea in much greater detail, akin to doing a research paper on it for my MBA or something, which I don't have the time to do.
As to your questions, I will try to answer:
As is now done with state and local sales tax, for simplicity, all items should be taxed at the same rate, except for my two exemptions, housing up to a threshold, and food. In some states, groceries are exempt now, and it works well, it is simple to do with the universal barcoding system. Restaurant food would not be exempt.
Services I am not sure, I would need much more information in regard to what the rates would be without it or with it, and the problems associated with it. I don't think though that services would be taxed, as they are not now in regard to state taxes, etc.
Commodities, I'm not sure what you mean, only retail items will be taxed, the middle man buying commodities for resale is not the end user, so no tax if that is what you are asking.
Your question about taxing gross revenues, no, the tax would be applied and collected pretty much like it is now for state and local, tax is collected for taxable retail items at the retail level as the taxes are collected by the retailer, that would be part of the beauty of the tax, the infrastructure is already in place.
Rentals, I'm not sure, probably so, to avoid the tax dodge that would be used, but more study would be needed on this issue.
There are things to be worked out, but the system we have now has how many thousand pages of tax code, ican, and it is so complex that people make a living studying this stuff.
Some of the things I like in theory are: Everybody would be aware of what percentage the feds are taking from them, rich and poor alike, it taxes at the point of spending instead of productivity which I think is a healthier way to do it, it would free businesses from income tax, etc., which would bring the price of products down significantly, and would make every product sold in America subject to the same sales tax rate regardless of where the product is made, which would unleash a very powerful competitive surge in the ability of domestic business to compete, and a sales tax would make every drug dealer and tax cheater pay taxes, which is a huge chunk of economic activity now escaping notice. And it would put alot more money into the peoples pockets, before they go out and buy stuff, stuff that will be cheaper, before tax, when they buy it, but when they buy it, they pay the tax right then and there and it is done with.
Finally, I want to see a serious debate with the experts laying out what would happen, the tax rates, how it would work, and an agreement that the IRS income tax would be eliminated at the very same time, before I would possibly endorse it. I am endorsing the idea for serious consideration, not for sure the implementation yet.