I accrued most of my "wealth" (estimated currently at about 200 sojs worth of items and 32 sojs) from good old fashioned non-bot Pindle runs in Hell mode (stopping to shop for cruels of course), and NM Diablo / Meph runs. All it takes is one so-called Godly item to get you started. My career in this sick, twisted, soj based economy was kicked off by a nice Etheral Titans on my first NM run ever. Just like any other economic system, buy low and sell high!
P.S. I have run 6 chars to lvls above 90 and have NEVER EVER seen a soj drop.