My mother passed away without a will a month ago. She owned a house with my stepdad in Albany, NY. He still lives there. I live in FL. What portion of the estate value do I get as a result?
IANAL. I am not your lawyer.
Assuming that they bought the house together, and are both on the title, your step-father would, as a surviving owner, take sole possession of the house (and it wound not enter your mother's estate). If she bought the house before they married and he moved in, and he is not on the title, it would theoretically enter her estate, but there may be additional rules as it is his residence.
As your mother lived in NY, NY law governs her estate.
If the estate is worth less than $50,000, you would get nothing.
If the estate is worth more than $50,000, he would get $50,000 plus half of the remainder, with the other half of the remainder being split between your mother's children. You don't mention any siblings, so I would assume you don't have any, in which case you should receive:
(Estate_Value - $50,000)/2.