If you read the wikipedia page http://en.wikipedia.org/wiki/United_Club it says you can buy access to United Club, but doesn't say that about the first class lounge. In fact it says:
"the access rules are significantly more restrictive than for United Club. Access to Global First Lounges is generally restricted to United Global First passengers, Star Alliance First Class customers, and Global Services passengers confirmed in Business Class."
In the first class lounge you get free food and drink including alcohol. If you could really get in for $50 a day, you could easily eat and drink that much worth.