yes...and no, it all depends on the night, some nights , for example Judgement Sundays are very very rarely discounted so if you definately want to go you will have to pay the price, but other nights can either be discounted or you get a deal, free buss, free drink etc. The Pussycat bar in San An is very good for tickets, they helped me out this year . It is worth remembering that numbers are down this year, no matter what people say, compared to the same time last year numbers are down alot this year for my 2 visits to the island (start and end of June), so even if the ticket prices done move much things like drink price might have. For exmple i saw tickets for Tiesto , normally 50 Euros and a sell out , going for 37Euros with free bus and free drink.
In the Ibiza Sun news paper they were saying many hotels were only managing 60% of the numbers compared to the same time last year , so get out there and shop around.