S-05 is $3.75 and Notty runs about $4.50 around here. I used to wash yeast and typically had good results, even after 4-6 months in the fridge.
I've since taken up making slants (following instructions on the HBT sticky), and would highly recommend this. As with everything else in homebrew, there is a little investment in tools, but it's very easy, and I can fit about 2 dozen slants in less space than 6 mason jars of washed yeast would occupy. It frees up space in my fridge for that other stuff, what's it called....oh yeah, food.