I used a home made mix. I have one of those cheap Harbor Freight Cement mixers that I used to mix up my soil. What I put in was
one 5gal bucket of peat moss
one 5gal bucket of Pro-mix
one 2gal bucket of Pearllte
three 5 gallon buckets of fine bark.
I mixed this up well and used it to fill my self watering buckets. Just kept making a bunch with this same ratio, and it seemed to work out well. I did put a handful of Bone meal in each bucket when I repotted the peppers to them.
The bark I got at the local place that sells top soil. Had them bring in 20 yards, so I mixed up a bunch in my garden to help keep it light and drain well. Up here in the Pacific NW, the soils seem to get heavy due to all the rain.
Found the buckets on Craigslist. Some kid worked at the local dairy Ice cream place and had loads of buckets for sale at 1 dollar each. That made it easy to buy a bunch.
Forgot to add. I originally got info about the mix based on one that is one the web It is called 5-1-1 and is credited to a guy called Al Tappa. You will see that several of these mixes add garden lime to the mix and I think it is a good idea, since this stuff is pretty neutral and could use something to get minerals like calcium in the soil. I know once my plants were growing, the bone meal seemed to last, but then the plants were small and under lights, they needed cal-mag pretty often.
here is a YouTube video on it. It is a bit different from mine, but the idea is similar
http://www.youtube.com/watch?v=HPOATQ3nxXY and
http://www.youtube.com/watch?v=Ixp_UI6AfwU
Here is a link to a discussion on using this as a base and calculating cost
http://gardenish.wordpress.com/tag/5-1-1/t
The main idea is to just get light and self draining soil.