Stu approached a soft-drink vending machine marked, "60. Insert coins in slot. Change returned below." The machine presented several large buttons, each with the name of a soft-drink. Stu inserted three quarters and pressed the only button labeled "Jolt." No drink issued from the machine, however. Instead, a sign near the coin slot lit up with the message, "Selection unavailable."

Stu grunted and pressed the lever marked, "Coin return." He wanted Jolt or nothing. He got nothing. He tried the lever several more times, adding a curse and a kick, but the machine held on to his 75. He stepped back from the machine and reconsidered. Sighing, he pressed the button labeled, "Fanta." A can of Fanta dropped into reach--but not his 15 change. Stu repeated his earlier attack on the coin return lever and got the same result: no change. Muttering, he stomped off with the Fanta.

Setting aside the impracticality of actually bringing suit for so trivial a matter, analyze Stu's experience in terms of contract law.