I believe at the last count, the Leave camp had spent the so-called saving that would arise from leaving the EU eleven times over already. In other words, they keep promising new things on a near daily basis, which are all due to be paid for with the same relatively small pot of cash - but they never make that aspect clear.
So for anyone not following the subject very closely (i.e. the majority of the electorate) it sounds at face value like a Brexit would bring a cascade of goodies, whereas at best they'll get ONE thing from it - after that, there will be nothing left in the kitty because all the savings will have been spent.