Last year we went early in the morning (around 8:30 or 9:30) for the reduced admission entry ($25/$30 Euros). We were planning on getting in at the reduced price and then leaving to get back to our hotels for some rest. When we wanted to leave we were told that if we left we couldn't get the re-entry bracelet. The re-entry bracelet is only available for patrons who pay the full $50 Euro entry. We were so mashed up that we left, went home and slept, and came back much later in the evening and paid the full $50 Euro entry.
So my suggestion; pay the 50 bucks to get in, get your bracelet, you are allowed to leave once (so choose wisely), and then come back later in the night/evening.