In past years, it was easy to exchange US dollars for shekels in Jerusalem. Many small retail stores did money changing on the side. Is that still true? How much better is the unofficial exchange rate than the official exchange rate? Are the exchange options basically the same in Tel Aviv?
There are hundreds of money changers all over Tel Aviv. Most of them charge a relatively small currency spread so there's little point in walking around for comparision unless you're changing thousands of dollars.
You can check out the latest cash exchange rates at the Israeli Post website:
All Postal Offices in Tel Aviv provide money changing services. The current spread for the postal office is ~2.4%.
When looking for
bureaux de change in Tel-Aviv, try to find someone who charges similar rates to the link above.