When traveling in Israel, I would suggest that it's pretty much mandatory to get yourself a cache of snacks! There are a variety of reasons behind that: many of the historic sites are several hours' drive from each other, many restaurants shut down for Shabbat, hotel room service that's supposed to be 24 hours might not really be ("We just have salads . . . it would be better to wait for breakfast,"), vending machines aren't a cultural phenomenon there, jet-lag might be driving you to starvation, hot weather is depleting.
That's why, during my recent trip to Israel, I followed the advice of other world -- and worldly -- travelers: head over to Super Yuda, their "supermarket". Super Yuda is not what we in the US would think of as a supermarket, the huge barns that we have in the suburbs. Rather, it's a smaller city market, the type of which is springing up all over urban enclaves in the US and in Europe.
Even so, there were plenty of both exotic and familiar things that one can take back to a hotel room, especially if you have a fridge. I would say the prices were about what one could expect in a city grocery in a more populated US city -- not outrageous, not cheap. Buying cans of iced coffee and bottles of water will surely save you money from what the tourist stops charge.
Israelis love olives at every meal and Super Yuda has the kind of olive bar seen in upscale grocery stores. There's also a beautiful selection of locally grown fruits.
I noticed a distinct marketing style with Israeli foods: as you'll see in the slideshow, they like to sell products with the face of a personality. That's kind of going out of fashion in the US -- we don't really have any new Mrs. Buttersworths, Uncle Bens, Aunt Jemimas, etc. Even Wendy's has changed. What's taken their place is the endorsement of celebrity tv chefs.
Super Yuda had a variety of iPhone accessories that I badly needed and they do take US credit cards. They're open 24 hours! According to Haaretz, the store pays a fine when it is open on Shabbat.