I was about 12 when the Chopper was in fashion, but despite my pleas, I never got one. I think they were relatively expensive at the time, about £45 IIRC?
If I HAD managed to convince my parents that my life depended on owning a Chopper, the purple one in the OP would have been my choice.
Edit.... Doh; yes £45 would fit in with the 92p per week for 50 weeks thing.
According to online inflation calculator, £45 in 1974 is the equivalent of £442 now. So no wonder my pleas fell on deaf ears, with another 3 sons for my parents to buy Christmas and birthday presents for!