When hosting a conference, it is important to remember that attendees will need something to carry items that they amass at the conference. You can take advantage of this opportunity and place your company's logo on conference bags for attendees to carry.
Instead of footing the bill for the bags alone you could invite others to share the space on the bag and the cost. You could end up with a longer lasting, better bag that will no doubt get used again. You still can keep a nice size space for your logo, maybe even an entire side for yourself and sell of space on the other side.
A conference bag would be super nice it it came with surprises already inside. A helpful sponsor could map out the layout of the event area so everyone could find the powder room and beverage stands. Depending on what the gathering is focused on other items could go in there too. A local guide is a good idea if the event will last for a few days. A schedule of events is good for everyone to have as well.
It would be ideal if it is within budget to get a bag that is good enough to last long after the event is over. If this is the case then your company will benefit from the long exposure of the bag imprint. You want it to be no trouble for someone to hold on to all day so look at all the types of handles offered and compare costs too. There are really nice bags that can bear a logo, and could be sold for a minimal price.
If an attendee at a conference has a decent bag to carry all the stuff that they got around in then they will probably end up spending more time wandering around the event floor. This is what every one of the sponsors is after. You want people to hang out and talk, meet other people. It is what these events are all about. If people are comfortable enough to hang around and make connections then the event is a winner.