Zerex is like $5 plus a small bit for shipping and handling. You are spending a WHOLE lot of time trying to avoid like $10 worth of mechandise (it shouldn't cost more than $5 to ship). That 4 oz bottle will treat 80 oz of distilled water.
DangerDen
For HydrX, it's about $1.35 for enough to treat 33oz of water (plus S/H). I calculated it will take $8.78 to ship 2 bottles (to treat 66 oz of water) to me by ground shipping.
Swiftech Direct
You really think that fiddling around with baking soda and methanol is going to save you that much?