The most "saturated" points of nightlife in Tel Aviv are the Florentin neighborhood, HaTa'arucha Street, and the city's waterfront. From the outside, the clubs are unremarkable (they are usually semi-basement rooms with modest signs), and you have to pay from 40 ILS to get in.
Waterfront clubs and bars often have all-inclusive parties - you pay around 80-100 ILS for entry and unlimited access to the bar.