The Three Sisters is one of the frankest portrayals of “marriage as prostitution” (as Mary Wollstonecraft described marrying for material reasons) within all of Austen’s writings.
Miss Stanhope takes no pains to conceal her motives while negotiating her price:
“You must build me an elegant Greenhouse and stock it with plants. You must let me spend every Winter in Bath, every Spring in Town, Every Summer in taking some Tour, and every Autumn at a Watering Place, and if we are at home the rest of the year (Sophy and I laughed) You must do nothing but give Balls and Masquerades. You must build a room on purpose and a Theatre to act Plays in. The first Play we have shall be Which is the Man, and I will do Lady Bell Bloomer.”
Which is the Man is a play by Hannah Cowley about a fascinating widow who cannot make up her mind among several admirers.
In 1787 Austen’s family considered performing it at Steventon. Although other plays ended up being performed then, Austen was well familiar with Cowley’s plays, and quoted lines from them in her letters.
You can read it in Austenette’s Repository. Follow the link Which is the Man