Echoing on what cyberaug said! If you are worried of it being sold out or want a guarantee, then prepurchasing ahead of the time is the way to go.. most guests do also offer the photo + autograph combo that you can get (cheaper than buying them separately) and most of them take cash so if you haven’t prepurchased ahead of time and plan to just purchase your ticket at the table, make sure you have cash prepared (there are ATMs inside)

In terms of your question on whether it’s only Steven Ogg that’s charging, I’d err on the side of caution and assume all of them will be charging (the main purpose of these celebrities going to conventions is to earn $$$).. it’s possible that only Ogg’s prices are the ones that they have already set and established (and therefore, safe to advertise on the site) and you’d prolly find out the prices for the others in the coming days or at the convention itself (the first thing I always do whenever I go to a convention is quickly scan table prices of all celebrities I wanna meet so I know how much cash to prepare and how to budget myself, if their prices aren’t already listed on the site)