Take another look at the sentence:
Jim's last temper tantrum __________ $200. He had thrown an expensive titanium three-wood into the golf course lake, and his wife Nancy insisted that he hire a scuba diver to retrieve it.
The sentence requires the past tense of cost, an irregular verb that never changes form. Cost, then, is the simple past form.
|Verb||Simple Present||Simple Past||Past Participle|
Coss, the form you chose, is a spelling error. Before you continue, review the rules for irregular verbs.