500 level tickets went up from $10 a ticket to $13 I think. The flex packs guarantee you first three rows up to 24 hours before weekday games, and 7 days before premium games.
There is also the 20 ticket pack. With this one you get 20 tickets, you can go to 20 games by yourself, 2 games with 9 friends (actually max of 6 per premium games, max of 4 for the opener). You can also add extra 20 packs up until June 30th.
My suggestion would be to get the 20 ticket pack, get 4 for the opener before they go on sale to the public and sell 2, 3 or all 4 (depending if you want to go). You pay for your entire 20 pack that way. Although they are going to the card system this year so you probably can't sell your opener tickets, unless you walk in with the people.