Sales taxes on anything -- luxury or not -- are regressive taxes on the poor, because the poor spend a higher portion of their income on consumption than the non-poor do.
For example, let's say we have a uniform sales tax of 5%. A poor person with an income of $20k will spend almost all of that $20k during the year, paying 5% of her salary in taxes. (She might even borrow money and spend more than her income, meaning relative to her income the rate increases to more than 5%.)
Say for the sake of argument unpoor me makes $40k and I spend $30k, saving the remaining $10k. I pay $1.5k in taxes, more in absolute terms but less as a percentage of income (3.75%), which is the definition of a regressive tax.
There are other ways sales taxes tend to favor the unpoor. For example, a poor person will typically buy almost all goods locally and thus be subject to tax on all of them. This is not necessarily true of non-poor people -- more than half of my monthly purchases are tax-exempt because of where I make the purchase. (For example, when I buy software from American companies, neither Japan nor my locality nor most US states tax me.)
There are tweaks you can make to sales taxes which make them marginally "fairer" to the poor: exempting food and clothing, for example, which the poor tend to spend more on as a percentage of income than the rich. However, these tweaks get very complicated very fast (a lot of governments actually have a policy which sounds like "Exempting food sales but taxing prepared food sold for immediate consumption unless it is take-out except taxing hot take-out." I wish I was joking. My sympathies in advance to anyone who writes POS software for French bistros.) These exemptions also tend to cost the state a lot of money, because non-poor people spend lots of money on food, clothing, etc.
Anyhow, long story short: sales taxes are, and must always be, a regressive tax on the poor.
a lot of governments actually have a policy which sounds like "Exempting food sales but taxing prepared food sold for immediate consumption unless it is take-out except taxing hot take-out."
This sort of thing is absolutely true here in SF. For example, buying a sandwich at Subway doesn't usually incur a sales tax. But answer "yes" to "Would you like it toasted?" and suddenly your $5 footlong is now ~$5.50 courtesy the State of California. See http://thomashawk.com/2008/06/cheap-bastard-says-dont-order-...
“Hot prepared
food products” means those products, items, or components which have been prepared for sale in a heated condition
and which are sold at any temperature which is higher than the air temperature of the room or place where they are
sold. The mere heating of a food product constitutes preparation of a hot prepared food product, e.g., grilling a
sandwich, dipping a sandwich bun in hot gravy, using infra-red lights, steam tables, etc. If the sale is intended to be of
a hot food product, such sale is of a hot food product regardless of cooling which incidentally occurs. For example,
the sale of a toasted sandwich intended to be in a heated condition when sold, such as a fried ham sandwich on
toast, is a sale of a hot prepared food product even though it may have cooled due to delay. On the other hand, the
sale of a toasted sandwich which is not intended to be in a heated condition when sold, such as a cold tuna sandwich
on toast, is not a sale of a hot prepared food product. When a single price has been established for a combination of
hot and cold food items, such as a meal or dinner which includes cold components or side items, tax applies to the
entire established price regardless of itemization on the sales check. The inclusion of any hot food product in an
otherwise cold combination of food products sold for a single established price, results in the tax applying to the entire
established price, e.g., hot coffee served with a meal consisting of cold food products, when the coffee is included in
the established price of the meal.
Good golly, I am so glad I don't have to program anything like that in my shopping cart...
While you are correct in principle, if we were talking about taxing, e.g. cars that sold for over 100 000 dollars, it would be silly to argue that it was hurting the homeless more than rich people (I am ignoring potential side-effects of the tax with respect to employment, etc. here, so I'm oversimplifying massively, but I contend that the rough outline of my point is legitimate).
That said, I will immediately concede that the iPhone falls into a somewhat different price bracket than that.
For example, let's say we have a uniform sales tax of 5%. A poor person with an income of $20k will spend almost all of that $20k during the year, paying 5% of her salary in taxes. (She might even borrow money and spend more than her income, meaning relative to her income the rate increases to more than 5%.)
Say for the sake of argument unpoor me makes $40k and I spend $30k, saving the remaining $10k. I pay $1.5k in taxes, more in absolute terms but less as a percentage of income (3.75%), which is the definition of a regressive tax.
There are other ways sales taxes tend to favor the unpoor. For example, a poor person will typically buy almost all goods locally and thus be subject to tax on all of them. This is not necessarily true of non-poor people -- more than half of my monthly purchases are tax-exempt because of where I make the purchase. (For example, when I buy software from American companies, neither Japan nor my locality nor most US states tax me.)
There are tweaks you can make to sales taxes which make them marginally "fairer" to the poor: exempting food and clothing, for example, which the poor tend to spend more on as a percentage of income than the rich. However, these tweaks get very complicated very fast (a lot of governments actually have a policy which sounds like "Exempting food sales but taxing prepared food sold for immediate consumption unless it is take-out except taxing hot take-out." I wish I was joking. My sympathies in advance to anyone who writes POS software for French bistros.) These exemptions also tend to cost the state a lot of money, because non-poor people spend lots of money on food, clothing, etc.
Anyhow, long story short: sales taxes are, and must always be, a regressive tax on the poor.