A lawyer "deal of the day" is okay in New York. It's an unsettled question most everywhere else, but an opinion (PDF) by the New York State Bar Association Committee on Professional Ethics says that money paid to Groupon or a similar website is not an improper referral fee as long as it's a reasonable payment for the type of advertising. Further,
A lawyer may properly market legal services on a 'deal of the day' or 'group coupon' website, provided that the advertisement is not false, deceptive or misleading, and that the advertisement clearly discloses that a lawyer-client relationship will not be created until after the lawyer has checked for conflicts and determined whether the lawyer is competent to perform a service appropriate to the client. If the offered service cannot be performed due to conflicts or competence reasons, the lawyer must give the coupon buyer a full refund. The website advertisement must comply with all of the rules governing attorney advertising, and if the advertisement is targeted, it must also comply with Rule 7.3 regarding solicitation.
How far we've come since Bates v. State Bar of Arizona, eh?
HT: ABA Journal