Since Bulgaria is a party to the Hague Convention of 1961, all that is required to have your document legalized so it can be use in Bulgaria is an Apostille. The Apostille is issued by the Secretary of State in New York. Each state has a different agency that issues the Apostille (i.e. New Jersey Apostille are issued by the Department of the Treasury, Division of Revenue. In Florida Apostille are issued by the Secretary of State).
There are many other countries that have abolished the requirement of Legalization for Foreign Public Document and will accept the Apostille for international document legalization. So there is no need to visit the Bulgarian embassy or consular office for a stamp.
If you need an affordable Apostille for Bulgaria, you can call or visit the following companies:
Notary & Apostille Service