Index card

Oxford ruled 3 x 5 inch index cards The cheapest self-testing tool there is: question on the front, answer on the back, shuffle, repeat. Oxford's ruled 3 x 5 inch cards come 100 to a pack, and the lines keep small handwriting neat enough to read back at speed. The assorted pack mixes blue, canary, cherry, green and violet cards, which makes it easy to keep one color per subject, or to move the cards you keep getting wrong into their own pile. Paired with a permanent fineliner, a stack lasts the whole course, and unlike a flashcard app it never sends you a notification.