It's gonna be impossible for anyone to PM you when using an alias.  And even if they could PM you, don't expect anyone to jump on your offer.  This is a pay to play (eat, drink, or otherwise) hobby, not a dating site.

but I don't think you quite understand this board.  

First, of all, many ladies would probably take you up on your offer providing that you supply them with complete prescreening and that you pay their donation in addition to the costs associated with the night out on the town.  The commodity these ladies offer is their time and time = money.  Compensation must be provided for their time.

Secondly, if you believe that any of the ladies would be interested in spending an evening with you for ONLY the cost of their drinks, you are sadly mistaken.  Any lady on this board can go to a bar, at any time, and have their drinks paid for.

There are dating sites out there that may be more in line with what you are looking for.