I'll be at RWA National in San Antonio this year too, doing a workshop on estate planning for authors.
The national conference can be overwhelming for a first experience, especially for anyone who's introvert (which the majority of writers tend to be). I'd recommend starting with a chapter conference, to get your feet wet first. THe first RWA National conference I attended was so overwhelming (despite everyone being so encouraging) that I actually stopped writing fiction for a year, blocked by the awareness of how much I didn't know about storytelling.
I've been to the New England Chapter conference (and will be doing a workshop there this year; it's May 2-3), the New Jersey conference, and a couple events in Connecticut. The ones I've attended have all had top names in the genre, and a wide range of topics. Individual workshops vary in quality a bit, but there's always something to be learned, and there are so many workshops offered that you're bound to find some good ones for whatever stage you are in your career.
The chapter conferences tend to have registration fees in the $100 to $200 range, for a long weekend, often including meals. The RWA National fee this year is $460, I think, for non-members. Not a bad price for a very full four days of events (but only one meal, I think). Both types of conferences become more expensive if you have travel and hotel expenses. I'm a penny-pincher, and I still budget about $1500 for RWA National (which includes $600 for plane tickets).