Mayonnaise and ketchup most certainly aren’t kosher l’Pesach without Pesach hashgacha. They both contain vinegar, which most likely is made from grain.
There’s a lot of adulteration of honey, particularly if it’s imported (some “honey” from Turkey has been found to be 0% actual honey).
Since a lot of the items listed (e.g., extra virgin olive oil, coffee) are available at regular supermarkets, it’s unlikely that there would be price gouging. In fact, there’s so much competition in the kosher stores in the greater NY area that in many cases prices are lower than normal before Pesach.
An important way to save money on Pesach foods is to avoid highly processed prepared foods, especially those that try to mimic chometz foods. Things like cold cereals, pasta, and frozen pizza are way overpriced and don’t even taste good.