Yeah, I'd avoid those bundles. The best deals are always at the official pre-party venues (plus you sometimes get freebies eg transport or even the odd CD), though to be honest the tickets seem to be similarly discounted wherever you go - they'll all be "15 euros off!" or thereabouts.
Be wary of offers via the hotel mind you, we got some for Hed Kandi last year and found out that they weren't valid for that night, so we ended up paying 50 Euros on the door - ouch! (though to be fair, the hotel manager whinged at El Divino and managed to get us free VIP entry to any other night there, shame we had to go home grr!!)