It appears that the $300 should be per Defendant, and per Judgment (not per account). The statute says (emphasis added):
Â§ 8123. General monetary exemption.
(a) General rule.--In addition to any other property specifically exempted by this subchapter, property of the judgment debtor (including bank notes, money, securities, real property, judgments or other indebtedness due the judgment debtor) to the value of $300 shall be exempt from attachment or execution on a judgment. . . .
I would like to hear other thoughts on the subject also!