You can save a lot of money. But you can also pay dearly.
The cigar-purchase on the street is always a risk. On recommendation of the official advertisement Cuba?s, there is a notice to it recently, that you shouldn't buy any cigars in the street. Whoever doesn't have the necessary amount of money, a box of cigars costs even in Cuba between 70 (Montechristo No.4) and 350 dollars (the more expensive kinds), is easily tried to join black market-offers, which are in the area of 20 to 100 dollars. In this case, you should have a little bit knowledge for having a good deal, because there is not only the bad faked ware to buy like it's always officially purchased.