How much does genius cost?

I recently, finally, read Virginia Woolf's classic, A Room of One's Own. Her main thesis is that in order for a woman to express her genius, or at least her creativity, she requires a room of her own and an independent income of 500 pounds a year. Between dreaming of an afternoon in the British Museum and assessing my retirement strategy, I kept wondering what 500 pounds in 1928 would equal in today's dollars.

To begin, I needed to find out what the value of a United States dollar in 1928 was compared to today's dollar. According to this 2007 article, if we go by the price of gold, "the value of today's $20 bill is about $0.59 in 1928 dollars." Good enough, especially since my next source yielded 6 different values for this.
Next search: the exchange rate between the US dollar and the British pound sterling in 1928. I lucked onto this site, Measuring Worth, which has several useful calculators. According to the "Dollar-Pound Exchange Rate" calculator, the pound was worth $4.87 in 1928, and $2.00 in 2007. According to the "Exchange Rates Between the United States Dollar and Forty-one Currencies" calculator, one dollar was worth £0.21 in 1928, but £0.50 in 2007.

After covering some scrap paper and post-its and revising some initial calculations, I discovered that when Virginia Woolf said a woman needed an income of £500 per year, she didn't intend for that woman genius to eat ramen in an efficiency.

In 2007, her £500 would be either $80,710.25 or $82,542.37. While Woolf believes that poverty or frugality in women has been a hindrance to their creative success, $80K seems like a lot of money for the basics of food, shelter, clothing, or even the solitude, travel and gourmet meals that Woolf decrees as essential to genius. Factoring in modern tools of creativity, such as a laptop and cable internet, or art supplies and agent's fees, Woolf's 500 pounds sterling could still go a long way. And I'm not even going to tackle converting the cost-of-living in 1920s London with that of 21st century Santa Fe. I guess I don't need all of it to be creative, but perhaps that's the real cost of genius?

Reassessing my retirement strategy, wondering if I'll ever see the British Museum, perusing the family tree to see if there might be some aristocrat or robber baron who may have left me a small sum with which to fund my creative unemployment while I write my work of genius...

Since I'm not permitted to use this forum to solicit benefactors, please feel free to check my math and equations instead.