My guess is that it's at least an '83 Model 310 (not a bottom feeder). If so, then it's a really decent ride and $150 is low - easily $200 if all tuned up around here, and I would suppose more money in hotter markets.
The presence of toe clips suggest that it could be even higher up in the chain though - If it's a 710 - then it's likely more like a $300 bike - (sort of on par with a Trek 560.)
The 310 /710 looked pretty similar and both had the Hi Ten sticker on the fork.
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- Auchen