Hotels are currently "giving away" rooms to those in the "biz". Have seen rates as low as USD25.00 per night in quality places like the Sheratons' for example. The island has been hard hit by a big slump in numbers from it's largest market Australia, and they are doing all sorts of things to get the people back.
Check the usual chains/suspects out, but also hit some of the Bali www websites for super specials.

As far as getting there, not sure who you are with (as in carrier) or what benefits you get with other carriers, but CO fly there from GUM with Air Mike subsidiary, SQ from SIN, MH from KUL, CX from HKG and JAL from Japan. QF also fly there from SIN PER and DRW and a limited service at the moment from SYD. Garuda is of course the logical choice, however, they don't tend to interline with many other carriers. If you can get to somewhere in Asia like SIN, then you may find a very good fare on the Garuda www. Failing a direct routing into DPS, try looking at getting into CGK - domestic flights between Jakarta and Denpasar are frequent and dirt cheap - even an ID50 firm space won't hurt too much.
My main concern of course is the conference - non-revving into a place that has limited flights at the best of times is always hard, let alone with something like this on. Maybe getting yourself to Asia, then either grabbing a www special or an ID50 firm may be a better option.

Cheers.