Very good, very cheap, natural, aluminum-free deodorant

I have tried every single kind of 'natural' deodorant out there and every single one has failed Arizona weather in a tank top. I don't mind a little perspiration, but I don't want to be "that stinky girl". Finally on a whim I mixed a little baking soda with some water and used that. Lo and Behold, it's the best stuff out there by a mile. Even better, after using it for about 2 weeks, I've found that I really only need to put it on once or twice a week. I don't wear polyester, so I can't tell you if it would hold up to that test, someone else will have to report on that. You might be thinking...gross, it must feel like sand in your armpits and leave white marks everywhere... Nope!
Here's how I do it:
Mix a small amount (quarter teaspoon maybe) of baking soda with just enough water to make it liquidy, not pasty (a couple of drops), mix it up with your finger, apply. I mix it in a tupperware container, so if there's extra I can save it for another day. Adjust amount of baking soda as needed.

Old annual cost of trying out new deodorants: about $20
New annual cost of deodorant: about 35 cents