Definitely agree with the 'more expensive at night', and the rates to ME appear to be whatever the taxi driver charges and you agree to pay.
My tips for taxi drivers are
1) Make sure it's a real taxi, not a gypsy. Real taxis have TAXI on the license plate.
2) If you think you're going to use a taxi a lot, develop a relationship with a driver, like TTOL sponsor, Wilfred Brooks. His info is on the TTOL sponsors page
3) ALWAYS confirm the price before you get in the taxi.
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