I agree that the tourist card charge for Canadians and people from the United States is a 'bargain,' compared to the charges other countries apply to visitors. The reason for the tighter controls on tourists from Mexico should be clear to all. Immigration agents in the USA are emplowered as are their brethern agents in other countries - including in Mexico.

Thanks, issue now clarified. The tax I heard about was for those without tourist card or hoping to reenter Mexico.
I agree that countries are free to set whatever visa/entry charges they want to in order to deter visitors; however according to my perhaps naive sense of fair play, an exit charge is below the belt (c.f. Belize). It's not pure evil like the Saudi exit visa, however.

Please clarify!
I came to Mexico across the land border with Guatemala at La Mesilla and Cuauhtemoc. They gave me this form that says $262 pesos, but doesn´t explain it at all.
I plan on staying in Mexico for several days before returning to Guatemala. I have heard I need to pay this fee to a bank before leaving Mexico, only if I stay for more than 7 days. But this border is small and has no banks! So i would have to backtrack to find a bank.
If anyone knows anything, please inform me, becuase I don´t want to get stuck at this small border town.

The form is the FMT (see my previous post). You have to pay the fee at a bank before you depart Mexico; it's not supposed to be paid at the border. The FMT forms that I've had, show a list of banks where the fee can be paid. I don't know what to do if there are no banks.
I'm not sure of the length of time you can stay in Mexico without paying the fee; I've heard 3 days, but I haven't found anything on the internet from an official source. How's your Spanish? Can you ask at the border?
Assuming you pay the fee, and now ready to depart Mexico, there should be no fee for departure. The official might ask for 100 or 200 pesos, but that will be for a double entry stamp.
If you don't intend to return to Mexico, just say "no regressa", hand in the form, and move on.
If you intend to return to Mexico, pay the fee and get the stamp. That will allow you to re-enter Mexico without paying anything.
If you haven't paid the fee, I don't know what will happen. Anybody??

For Americans http://travel.state.gov/travel/cis_pa_tw/cis/cis_970.html#entry_requirements states that you need an FMT unless you are staying less than 3 days AND you are within the U.S. border zone. So you need an FMT (or get fine on exit) and you need to pay for it at a bank.

John500, you have made a few "crossing from Canada to Mexico and back to Canada" references above; is there a Canada/Mexico border that I'm unaware of?
All of the Mexico borders are riddled with corruption & I'm fed up. At Chetumal, they now charge a greedy $200 pesos for a "multiple entry" stamp. What recourse do you have? Telling them "well it says online that there is no fee for a multiple entry stamp" isn't going to get you very far. Any of the other borders I've crossed through over the past year (Cd Cuauhtemoc, Tenosique, Tapachula) have all told me that a "multiple entry" stamp doesn't even exist, and you must pay $262 each & every time you visit the country.
None of these border facilities can provide me with written rules & regulations--not even in Spanish--for the FMT as it pertains to visiting travelers. Very frustrating.