Despite his misgivings about Ropers' automobile (it's a true lemon), Jack is very eager to buy it when he learns that he can get it for dirt cheap. Having a car would solve a number of the kids' problems. So they convince Roper to sell it to them, despite the fact that he's already promised the car to a used-car dealer (Tom Lacy). All sort of money-related shenanigans ensue as Roper, determined to make some sort of profit, realizes that he can get as much as $1200 for it. But Helen refuses to let him screw over the kids.
Overall, "Roper's Car" is a decent episode, with some good laughs, if maybe a few too many jibes at Chrissy's expense. It's fun to watch Norman Fell as Roper keeps trying to make sure that he comes out on top. He's NOT about to give the roommates an "equitable deal" if he can help it. Unfortunately for him, he's mistaken about which year the car is. It just goes to show the viewer that one mustn't be too quick to make assumptions, and the value of sticking to your word, even if a possible quick cash deal can come up.
John Ritter is in fine form, especially in an early scene involving eggs. The whole cast is great, really, including guest star Lacy as that common stereotype of the sleazy salesman. Fell does another of his priceless "insult the wife, smile for the camera" routines. And Suzanne Somers is endearing as usual, even if Chrissy is made to look particularly naive here. Some of the best moments involve the kids trying to work out their car schedule, and Roper uttering a mouthful about "the first word".
Good fun in general.
Seven out of 10.