The Leipzig forum is probably not be the best place to get information about FC Bayern tickets :-)

Your chances of getting a ticket for this game (or any FC Bayern Bundesliga games) through official chanels are ZERO.

As of July 31 the games against Bremen, Wolfsburg and Nürnberg are sold out, and for all other games the ticket requests already received by the club are such that even if you managed to navigate their website it would not help in actually getting a ticket.

As I already mentioned in previous posts, only 8000 of the 69000 tickets go into regular sales, the rest is for sponsors, season ticket holders, fanclubs and the visiting club. The booking of those 8000 tickets started in February on an optional base, so that almost all FC Bayern home games were already sold out even before this season started.

So if you want to see a game at the Allianz Arena it is usually better to try to see TSV 1860 in the second Bundesliga.

In your case, to get just one ticket, it is probably best just to go to the stadium on matchday and try to buy one at a reasonable price from the numerous people trying to resell tickets. Between the exit of the U-Bahn station and the stadium there will usually be dozens of sellers, so try to find the few who are not professional scalpers...