Here is a link for you to get all you need in one shot.
Bet it isn't as cheap, but there is the convenience factor.

Washing soda is no big deal. You can find it in the aisle with the rest of the laundry stuff. Borax too. I figured it out using what I paid, and I think with the original fels-naptha soap it came up to less than 5 cents a load compared to 25-30 for store brand detergent. Which does add up over time.

I make a very similar detergent, Juni. Then, I use a small amount of that detergent and mix it with a little washing soda, hot water, some drops of tea tree oil and some drops of eucalyptus essential oil. This makes a really nice all-purpose cleaner that I use in everything from bathrooms to kitchen counters.

Here's an article geared toward trimming the household supply budget, including tips on making your own cleaning supplies, from The Simple Dollar:

http://www.thesimpledollar.com/2010/...ping-supplies/

I'm LOVING The Simple Dollar--it's a great blog full of wise advice for finances and general self-realization.