The others have pretty much given you the info available on "earnings" here at HP. If you are including HP along with several others sites you may write for, it's a good addition. You'll make a few bucks a month (pay-out is at $50.00) but do not count on supporting yourself on your HP earnings,
The days that writers could feasibly do that are long gone.
It's a great place to write, Hellen, for various other reasons besides money. You will find the community of incredibly talented writers, some of the nicest, friendliest & most supportive people ever. So many of us have made wonderful friendships here with people from every corner of the world. It's a great place to let your muse run free & productive. I cannot put a price on the wealth of knowledge I've gained through reading the works of my fellow-writers. Peace, Paula