Persons required to file a declaration.

(a) Except as provided in subsections (b) and (c), every resident and nonresident individual shall file a declaration of estimated tax together with payment of such tax, if he expects his income or income from sources within this Commonwealth, other than compensation on which Commonwealth personal income tax is withheld, to exceed $1,000 during the taxable year. An individual means a natural person and shall include members of a partnership or association. An estate or trust shall not be required to file a declaration. Estimated tax is the amount which an individual estimates to be his tax due, less the amount which he estimates to be the sum of any credits allowable under the act.

(b) An individual having a total estimated tax for the taxable year of $50 or less may, if he elects, file his declaration of estimated tax together with payment of such tax at any time on or before January 15 of the succeeding year.