While there have been exceptions in the recent past, you NORMALLY cannot go from flight school directly to an airline. You should expect to work multiple jobs in between to build up the necessary competitive flight experience...

-CFI/CFII ASEL
-MEI
-Part 135 Night Freight (or possibly corporate King Air).

The ratings required to get a CFI job (Private, Instruent, Commercial ASEL, CFI Airplane, CFI-Instrument) can cost anywhere from $35K to well over $100K.

The lowest costs will be part 61 training at your local airport. The highest costs will ripoff "academies" and aviation universities.

Hint: No employer cares where you went to school or how you got your ratings (unless it was in the military). Unless you are independently wealthy, go for the cheapest option. Spending a bunch of money will not benefit your career at all, and you will not be able to repay the loans in less than 20-30 years on airline pay.