For a first date, things were going fairly well. We were at Megu, a pricey Japanese restaurant in Midtown Manhattan, eating perfectly cooked Kobe beef. My companion, a wealthy finance type, was telling me all about himself and posing questions that suggested he was interested in me. Then, matter-of-factly, he said, “Whether I met you on the site or at the Standard, you’d cost me at least 10 grand a month.”

The site he was referring to was Seeking Arrangement, an online network that pairs people possessing resources (“sugar daddies” and “sugar mommies”) with those, usually much younger, seeking them (“sugar babies”). I had become a member a few weeks earlier, partly as a social experiment and partly out of genuine desperation. I was frustrated with my job, which offered little upward mobility, and was thinking about quitting it to pursue my goal of becoming a full-time freelance writer. Holding me back were my lack of savings and my fear of sacrificing a regular paycheck. If I had a hefty allowance from a generous benefactor, though, I figured that I could take the leap comfortably.

The idea of wealthy older people supporting struggling younger ones is nothing revolutionary, after all—look what Peggy Guggenheim did for Jackson Pollock or the Tuohys did for N.F.L. star Michael Oher. So what if I had to tap into my inner geisha to secure a patron?

To overcome my reservations about walking the line between dating and prostitution, I told myself that any such concerns were the result of societal conditioning. The idea that mixing money and mating is inherently bad, I reasoned, was a fallacy based on our collective obsession with moralizing sex. Mating rituals involving the exchange of gifts—be they hunks of meat, small fishes, or diamond rings—are ingrained in many species, from apes to seabirds, to humans. It is only natural for males to target cues to fertility such as youth and beauty, and for females to be drawn to displays of resources. Why sneer at suspected gold diggers like Heather Mills or the late Anna Nicole Smith if they were merely following their evolutionary instincts?

With all of this in mind, I created my Seeking Arrangement profile. Since I was still a bit hesitant about how far I’d be willing to take my experiment, I signed up using the pseudonym Annabelle Walker. The site, which launched in 2006, has about 420,000 members, of which roughly one-third are sugar daddies and two-thirds are sugar babies (sugar mommies account for less than one percent). While sugar daddies pay $49.95 per month for a premium membership (or $1,200 a month for Diamond Club certification, which requires verification of one’s net worth through tax-return data), as a sugar baby I was able to join for free. I uploaded two photos and listed some general information about myself, and I stated “open, amount negotiable” in the space that asks what you’re looking for. (Seeking Arrangement skirts the issue of prostitution by promoting the exchange of “intimacy and companionship” for “gifts.”) I took a deep breath and posted my profile, determined to focus on New York–based single men claiming to be worth at least $10 million.

But back to Megu and my date, whom I’ll call Hank. (Throughout this article, I’ve changed the names of the men I dated to protect their privacy.) Initially, he drew my suspicion with the cocky, typo-ridden message he sent me on Seeking Arrangement: “i think i maybe waht you r looking for; read my profile and if you r interested drop me a line..you wont be disappointed.” Then I saw his net worth—$100 million—and the amount he was willing to spend on a girlfriend: $10,000 to $20,000 per month. That would be enough to cover my living expenses and leave me with thousands in disposable income. The rest of Hank’s profile, which told me that he was middle-aged, played sports, and worked in finance, was of less interest.