I have a rear wheel that's been living in my closet for the pass 6 months and I want to convert the Shimano freehub to a singlespeed. There's a deal on nashbar.com for a singlespeed convertion kit, but I already have a 18T cog I got from a Gusset Singlespeed conversion kit that I want to use for the new rear wheel. I already have a 11T SRAM lockring. I just need cog spacers.

So where can I find cheap deals online for just cogs spacers? I'm talking <$5