When you register for our state conference, you receive a time which is when you may go and buy at the used book sale. Folks who are willing to volunteer and help sometimes get to make their purchases first. Make sure you know what it is you are buying, what the retail price is and, if it is a complete curriculum, that you have all the pieces you need. A well-planned conference will have many types of workshops to attend. Most state conferences will have seminars on your state laws and ways to deal with them.
Vendors normally give a variety of workshops.
There is nothing wrong with that, just make sure you know that they are probably selling something. You may want to attend some of these workshops if you are considering purchasing the product. Most conferences will also have a keynote speech which is normally given by a nationally known homeschooler. Try to attend these, they can be very worthwhile. Remember, in a few years, it could be YOU up there talking.