I am looking to spend 10-12 months teaching english in Poland.
You'll work about 8 1/2 months, and get paid for 30 weeks. The school year starts in the first or second week of October, and ends sometime in June. You will not be paid for the Christmas and two-week winter break, nor for holidays. Summer work is very difficult to get, and often paid at half the normal rate.
I am not looking to make much money, just breakeven.
That is the best you can expect.
I have a lot of experience advertising, networking and promoting private lessons.
For the amount of time you will be staying, building up a clientele of private students would probably be more trouble than it's worth, especially if you do not speak Polish.
I get that CELTA is the way to go, but is it really worth the expense considering my situation? Is it worth paying $1400 when i could to a TEFL course for $600-$800 (i-to-i tefl)
The Celta will reduce your monthly cash in hand by 600 PLN. That might mean that you will be in the red at the end of the school year.
You will need a CELTA to teach in a good school in the attractive cities for sure, like Warsaw, Kraków and Wrocław. Competition is fierce in Kraków and Wrocław, so avoid these cities.
Without a CELTA, it is unlikely that you will get hired by a good school in a desirable city. You might land a job in a Callan, Avalon, Direct Method or Berlitz school, but these are generally lousy schools with lousy conditions that pay peanuts, and sometimes not at all, so avoid these schools like the plague.
Without a CELTA, you might find a job off the beaten track somewhere in some small or mid-sized town like £omża, Augustów, Piła or Kielce. Finding openings there is a challenge. The advantages are that schools are desperate for teachers, that wages are about the same as in the bigger cities, and that the cost of living is considerably lower. The disadvantages are that if you are not satisfied with your school, there's often nowhere else to go, and that village life is not for everyone.
I have a 4 year undergrad in Finance and have job opportunities lined up, so I don't want to make this a career or live permanently in Poland.
Then why would you want to teach in Poland? It hardly seems like a logical choice. Either accept a job and start working, or spend your time beefing up your qualifications so that you can find a better job. At best, teaching in Poland would be an extended vacation after which you have nothing to show for it. At worst, you could end up in the red. You certainly have more attractive options for spending a gap year than teaching in Poland. Explore those.