Poster rliz offers some good advice.
I am fortunate in that I personally attend a local clinic that has a sliding scale payment policy and pay only $11 per visit to see a psychiatrist. He often gives me sample medication for several months at a time for nothing.
Walmart and several other retail establishments offer generic medications including some antidepressants for as little as $10 for a 90-day supply.
Non-medication treatments for depression usually follow standard health advice, such a balanced diet and regular physical activity of some kind.
If you are a reader, I recommend Andrew Solomon's "The Noonday Demon" and David Burns "Feeling Good" to educate yourself about your presumed condition.
In addition, many of the companies who make antidepressants have patient assistance programs that provide medication free of charge.