You could actually use soil in a drip system, but if your looking to go a different route I would say GrowStones or rockwool. GrowStones are, and I quote, 'breakthrough, high-performance growing mediums that are 100% recycled glass and 100% American made. The highly porous, chemical and toxin-free hydroponic growth mediums and soil aerators are engineered to deliver proper air and water balance in the roots without the danger of overwatering. They can be customized to fit a wide range of plants and climates as well as different growing systems.' I use GrowStones and I love it! Rockwool is also a great alternative because you do not have to re-pot when using it; the plant can remain in the rockwool for the remainder of its life. I have provided a link below to my favorite hydro store, they carry Grodan rockwool.

Here is a link that might be useful: Hydro Store

This past summer I had 12 bato buckets in one system and 5 in another. I used expanded shale, cost me about $40 for 550 pounds (bulk in the back of my pickup). I checked the ph a couple times and it was OK, so I never checked after the first couple weeks. In the 12 bucked system I grew tomatoes, cucumbers, and peppers. The 5 bucket system was my herb garden with a couple types of basil, mint, stevia, and dill. I used Masterblend per MHPgardener's recipe.