I think the prices shoot up for last minute bookers , if you look at the following weekend which is less than 11 days away the price for the same flights is £ 82 , you booked 11 days before the flight and paid a bit less , I think our flights cost around £65 ish back in January , I really doubt the flight will be full ,
Have a look on
http://www.muenchenticket.de which gives prices for the MVV network , I think a city/airport ticket is 11 euros , this will get you from the airport to the city centre and can be used for the rest of the day on the network and the day tickets are 5.6 euros which lets you travel around on the underground and trams .
So you would pay 11 euros on Sunday , 5.6 on Monday and 11 euros on Tuesday which would cover your airport transfers and unlimited travel around Munich on all 3 days .
The website also sells concert tickets and I bought all our tickets through them , the only problem was I couldn't find an " English" button so with my limited schoolboy German I bluffed my way through the booking process , I did get in a bit of a mix up on one set of tickets so I sent them an email and received a perfect translated reply !!