The value of the Israeli Shekel (ILS) tends to be somewhat heavily linked the the United States Dollar (USD). Though major events can of course alter this, over the years they’ve remained relatively stable against one another. For example, throughout the last year, the Dollar has traded within a tight range of 3.7295 – 3.9889, even during relative instability.
Almost always, especially for tourists using hard currencies such as the Dollar or Euro, the most advantage way to buy Israeli Shekels is to wait until in the country. Israeli high street change shops usually offer very competitive rates, and in particular the Dollar can be bought at a very fair rate.