Question: Am I expected to patronize the local Jewish grocery store if the Pathmark Superstore is cheaper or more convenient?
Answer: Dayan Y.Y. Weiss zt”l addresses this question directly in Minchat Yitzchak (III:129) and discusses there the opposing opinions of the Rama and the other achronim mentioned last time.
He leans towards differentiating between a small price difference, in which case you should patronize the Jewish store, and a large price difference, in which case you are not required to suffer a loss. [This is also the understanding of the Chofetz Chaim (Ahavas Chesed 5:6-7) in the opinion of the Rama.]
However, Minchat Yitzchak concludes that if the small Jewish storeowner will be driven out of business and lose his livelihood, there is a greater need to support him even if there is a significant price difference, if the customer can afford it.
Thus, according the Maharsham and other achronim mentioned last time there is no requirement to patronize the Jewish business if it more expensive. However, it is meritorious to follow this middle position and patronize the Jewish business if it costs only slightly more, and certainly if it is only an issue of convenience, as mentioned last time in the name of the Maharam Shick.