SummitPost.org

The majority of the $45K is for the flight from Punta Arena to Union Glacier. There is only one company, ALE, that has permission and rights so there is no competition or alternative other than perhaps taking a boat to the continent edge and skiing in, but that's an entirely different adventure!

I believe that it is possible to do without a guide, but it isn't much cheaper and you still have to use the same company to get there.