Sentence error

[midspring]

Go back 10 years or so, and solar heaters used to be very expensive, this was because
power prices were only around $0.07 a KwH and Solar panels used to cost well over

$5,000.00+.

Is there any error with the sentence? Can "Go back 10 years or so," considered as sentence or it acts like a sentence?

[5jj]

Welcome to the forum, Midspring.

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