looks like i was a little behind the trends. bmx bikes became the de rigeur rides prior to upgrading to 10 speeds. thought it was closer to 1980 when they became popular but heres a mongoose from 1975. they were pricey too if memory serves.
My first bike was a one-speed Schwinn, then the five-speed stingray knock off. In fifth grade I got a mitsutani 10 speed. In seventh grade I returned to the sting-ray style because I missed going off jumps and popping wheelies. I got a Webco bmx bike in 1976, my sophomore year, which I hardly rode because I wasn't good enough at the tricks and was constantly challenged by kids who could shred. I wasn't great on a skateboard but could do 360's well enough, fortunately the ollie and other more advanced tricks hadn't been invented yet and because of Portland's climate there were no swimming pools which I certainly would have sucked at riding, so the skateboard was a relatively shame-free source of transportation for my 15th year. Getting my driver's license brought some relief to my wheeled woes.
The alternative was an English racer. A full size bike with regular handlebars. Usually 3 speeds in the handle and grip breaks and skinny tires.