Installed the script on March 23, 2013. I haven't touched it or promoted it.
All traffic is from organic search.
Since I'm using a shareware script my commissions are 65-70% of total. Script supplier gets 30-35%.
My share of ShopZilla commissions:
March: 26 unique visits - $0
April: 173 unique visits - $6.19
May to date: 588 unique visits: $5.22
Looks like it's worth promoting!