I think I have always used these two words interchangeably without noticing until my professor was saying how some students misspelled the word and he was amazed.
Can someone tell me when I should use paid over payed?
I searched for a similar question and got even more confused with this title: you paid for a persons drink and expect to be payed back.
Paid or payed is the past tense of pay depending on the sense of pay. The first sense is the usual one of giving someone money while the second sense is to seal (the deck or seams of a wooden ship) with pitch or tar to prevent leakage.