I've been to the previous two held in NJ, and I have my tickets for this one.

They're not as wild as AVN, and there's more stars at AVN, I think, but the Exxxotica conventions are pretty good for meeting the stars, and getting autographs, especially if you can't afford to make it to AVN.

The stars charge for the 8x10s they will autograph for you.  Some have a camera and you can have a picture taken with them, printed, and signed.  Or you can take pictures with your own camera.

The prices for these photos vary greatly:
autographed 8x10s - anywhere from $10-$30 each (average about $20)
Picture taken with the star with their camera - $5-$20
Picture taken with the star with your camera - $0 - $10
Picture taken of the star with your camera - $0 - $5

Of course, these are last year's prices and may have gone up.  

Some of the stars will be selling their latest dvds at cost but they'll autograph them for you.  Some of the stars will have other things for sale, too.

There are also usually booths selling t-shirts, sex toys, condoms, energy pills, blood testing services, and more.

As for making appointments with stars during the convention: it can be done and I know several who have done it.  But, the majority of the stars will be VERY busy during the days of the convention and if they're not too tired after the show closes down, they go out partying.  I know there's going to be an after party on, I think, Saturday.  Last year the party was at the strip club in Lodi called The Harem.  I think it'll be the same again this year since they are sponsoring the VIP lounge.

Note: I'm not affiliated with the show in any way.  I'm just an attendee and I do not speak for the show, the stars, The Harem, or anyone but myself.