I agree. Also, in the example of lawn-mowing, perhaps the homeowner simply enjoys caring for his own property, and would do far more than $10 worth of work in the process of mowing. And, in addition, this person might find the prospect of mowing another’s lawn for a mere $10 to be an insult.
In the case of the wine, what one can buy from a wine merchant for $50 would far surpass in quality what one might buy in a restaurant for $50. Th two cases are not contradictory behavior if the wine drinker perceives the $50 bottle at home to be a better value.
Why was the $50 bottle of wine "just lying around"? My interpretation would be that the person had been received it either as a personal or promotional gift. He might not have spent $50 on the bottle if given the choice, but once he has the bottle what's he supposed to do with it if not drink it?