Unfortunately, while it was never cheap, over the years it has gotten much more expensive and I no longer work in NYC so it's not so easy to grab a bottle during my lunch hour. In recent years, I've taken to the internet for purchasing. This go-round, google told me that there was a sale at Stuff 4 Sewing for cheap, cheap, cheap. The sale can be found here.
I found an online coupon and qualified for free shipping and I ended up getting it for about $33.00 per gallon with shipping. To do so, I had to buy three gallons which means I shouldn't need any more until 2015!
God, I love a sale and a coupon!! ~ksp