Standard and Poor of Living

I work in the tourism industry in a place that gets a lot of international tourists. A $125-per[-summer]-night motel (yes, motel, not hotel) room is high but not excessive to a middle-class American, but that price must be obscene to someone from Romania, the Sudan, or China.

When the media reports of laborers in Thailand making $1 per day, most people's immediate reaction is, "Oh my gosh, how can anyone live on that?" But you have to keep in mind, too, that things cost a lot less in Thailand than here--$1 goes MUCH further. I've heard reports of 4-star-hotels going for $20 per night, and lavish six-course dinners costing $10. (OK, my memory might be exaggerating, but you get the picture.) So, a $1-per-day income in a country like that, while still far below the average relative income of someone in the U.S., is not quite as low as it sounds at first.

I'm not an economist, but I'm intrigued about how all of this relates. In my completely ignorant and uneducated view, I see two factors:

1. Income
2. Cost of living

So, here's how I see this all interacting from my view.

IN THE U.S.
1. Income: Within my country's borders (the U.S.), my income qualifies me for lower-middle-class status

2. Cost of living: I like to call myself a poor, starving college student, but I'm lucky enough to have low living expenses and a decent job. I can afford the food I need, a well-running car (not anything fancy, mind you), and a laptop computer. I can also afford to take a few much-needed trips each year.

TRAVELING TO SOUTHEASTERN ASIA
1. Income: Let's assume I keep my American job and take a two-month trip to Thailand.

2. Cost of living: That same income will go MUCH farther. I'd probably be able to afford a nice seaside condo and perhaps a housekeeping service. I might even be able to make payments on an imported luxury car--a Mercedes, perhaps.

MOVING TO SOUTHEASTERN ASIA
1. Income: Let's assume I take a job in Bangkok that is similar to my current job. My income is cut 90%.

2. Cost of living: My new income in Thailand qualifies me for lower-middle-class status. I have to share a flat with a couple of friends, rely on public transportation, and can't afford many imported-from-America items.

LIVING IN SOUTHEASTERN ASIA AND TRAVELING TO THE U.S.
1. Income: My small income per year is well below the U.S. poverty line.

2. Cost of living (traveling): I can barely afford the bus ride from the airport to my old house--it's half a day's Thai wages for me. A Taco Bell burrito costs as much to me as a four-star restaurant back in Thailand.

There's a third factor, too--the exchange rate. Currencies rise and fall against each other--one day, the Euro is strong and the dollar is weak, and travelers to Europe see a higher cost whereas travelers to the U.S. feel slightly richer in comparison. Goods imported from Europe are more expensive (a Mercedes might cost $2,000 more).

So what my actual QUESTION is, then, is can someone devise a simple-to-understand way to put all of this data together? Purchasing power parity and GDP lists are useful, but I want to know how it applies to my daily life and to the daily lives of people in other countries.

The Economist's Big Max Index is a very useful tool for this, but it doesn't quite go far enough. Let me pose some hypotheticals followed by some questions:
1. In order to pay for a Big Mac in the U.S., I need to work at my job for about 15 minutes. Or, put another way, I can buy 4 Big Macs per hour.
2. In order to pay for a Big Mac in Argentina, I only need to work about 8 minutes. I can afford almost twice as many Big Macs there as I can here, or 8 per hour. Therefore, can I conclude that my standard of living is twice as good as his?
3. How long does an Argentinean need to work to pay for a Big Mac? Let's assume an Argentinean in a similar place in life as me makes half as much as I do. Therefore, he needs to work about 15 minutes to pay for a Big Mac--the same 4 per hour as I can buy. Are our standards of living comparable?
4. The Argentinean comes to the U.S. He can only afford 2 Big Macs per hour. Is he poor?

Let's assume that a Big Mac is a fairly good measure of the average price for food. (That is, a dinner at McDonalds costs roughly the same as a dinner at any other fast food joint, is cheaper than casual dining, and somewhat in line with food prices at a grocery store.) Regardless of exchange rates, in the above example, both of us spend about the same percentage of our income on Big Macs--that is, on food. Assuming transportation, housing and goods were roughly the same proportion of the Argentinean's income as it is for me, we'd both have roughly the same standard of living...unless you introduce that perhaps his food isn't as good as mine and his housing is ramshackle.

I think what the real thing I'm looking for is: what percentage of the average person's income is spent for a given standard of living? Yes, the Big Mac in Switzerland costs more, but do Swiss people make more? Probably not: I had a nurse friend in Germany who made about $1500 (USD) per month. Yet the cost of living in Germany is far higher than it is in the U.S.--gas is (or was, anyway) four times as much there as here, and even eating out was relatively expensive (the average meal bill as seen on our U.S. credit card statement was more for a party of four than it was at a similar restaurant back home). How did she survive? She was the housekeeper for a Catholic priest and paid no rent. (But not everyone can do that.)