Hi there,
you'd need to have at least a secondary school degree in order to become an airline pilot or to qualify for a so called "cadet program" - which is basically an airline sponsored flight training program. Emirates offers such a cadet program but only for citizens. So if you happen to be one, then that's probably your best way of getting into an airliner's cockpit - provided you pass the aptitude tests!
General sequence of flight training (pilot licenses): PPL, IR (instrument rating), CPL (usually combined with a ME = multi engine rating). It's also possible to get the CPL right after finishing the PPL, but a CPL without an IR is basically useless because it is limited to daytime VFR (visual flight rules) flights only and within a radius of 50NM (nautical miles) of the departure airport. For the ATPL (airline transport pilot license) you must have at least 1500hr, these hours are usually acquired as a FO (first officer = copilot) while flying for an airline or any other type of commercial operations, which require at least a CPL/IR.
Regrading the costs, difficult to say since a number of factors come into play (e.g. cost of living if training is conducted abroad, personal flying skills (usually overestimated), personal motivation, financial situation etc.) In general it can be said, commonly the training takes longer as expected (meaning more flight hours) and subsequently costs more money than initially estimated. A good rule of thumb is to add about 30% to the initial cost estimate based on the school's quote (since this is based on the absolute minimum flight hours, which are generally insufficient to be ready for the check-ride). I personally would calculate with a minimum of 50.000$ for the full training program, just to be on the safe side - no matter what the schools say! And don't forget to add the cost of living!
But as already mentioned above, if you're a U.A.E citizen, go for the Emirates cadet program! See link below - try hard and good luck!
http://www.emiratesgroupcareers.com/uae-nationals/