Andreas,
At my old club in Germany there were several prices depending if you
were a youth, club member in club aircraft, club member with your
private aircraft or non club member with your private aircraft. The
cheapest rates are as you mentioned. It also makes a big difference
that the German clubs have way more launches than 30 a week. It's more
like 150 a week or more. So the spread can be less.

Of course there are other criteria that the government supports these
clubs and some members to a small degree and they also charge by the
hour for their aircraft - though a small fee - but a fee none the
less. Their set up is just totally different, but my point is that
you can make good money as a club here in the USA with a winch where
you really can't with a tow plane. The tow plane is just very
expensive if operated by the club and if using an FBO, no money comes
back to the club.

All this changes, with a club owned winch and even charging the
astronomical fee (for a winch launch) of $15 per launch, it's a good
money maker which can be put to good use in a non profit 501 (c)(3)
club to buy aircraft, equipment, hangars, etc.....Even at $10 a launch
it's a good money maker. Perhaps the launch fees can be charged as in
the German clubs, depending on club status and aircraft. This would
encourage club membership as well as it's cheaper to launch as a club
member.