As someone who has repeatedly attended and presented at conferences in my field, I make it a point during negotiations for any new job to ensure these are funded fully but only if I am presenting; otherwise, I opt to share in the costs associated in attending with my employer.
Each and every company I have worked at in the past (and current) has a budget for training and professional development of its employees, some more than others; however, by making a case that I am giving back to a community of like-minded professionals and putting our name and brand out there during presentations, I have found this is an easy sell for companies for which I want to work.
I work extensively w/SAS and utilize a lot of the conference (SAS Global Forum/SUGI prior) materials in my day to day both for myself and our entire organization. By making it clear to my employers that I want to give back by presenting, I have opened organization's view on how the sharing of information benefits the business while benefiting the entire industry.
Make your determination and desires known when you sign on and, if that is not an option, make it clear to your management that you want to do the same thing. While I have received a variety of different types of pushback over the years for this view, they have all relented and ended up changing their world view when the benefits are presented as they are.
Conferences are not inexpensive (SAS Global Forum is usually around $3000 - $3500 for a single person encompassing travel, conference registration, lodging, meals, etc) but the ROI can be HUGE beyond that depending on the knowledge transfers that occur, the networking opportunities, and the new business development which I have seen from these conferences.
While I did not attend SASGF 2014 this year, it was solely due to my available time to develop a presentation topic, not because my company would not send me (this was my first missed attendance since I became involved in the SAS world) and I look forward to contributing to and learning from others in the future.
Best of luck.