I don't think the woman at the store is necessarily talking about prostituting herself, nor do I think that she is not independent and can't pay her own way (though, that may be true too, there's just no way to tell from that statement alone). In any healthy romantic relationship there's a dose of play and flirtation when it comes to many things, which also includes buying items for each other. It could all be a part of their private romantic game. Or, it could be that he is her sugar daddy - who knows? There's a great book about this topic, the name of it is "Games people play" by Eric Berne. He talks about both "good" and "bad" games in relationships. An excellent read.
Would I personally do it? Maybe
Depends if my personal need have been satisfied, like one of the posters above mentioned
