cheap IPTG ?

[Mike Rogers]

Another option that you can use instead of IPTG is using lactose as the 
inducer.  Although it is metabolized by some cell types its cost is 
still 5-10x lower than those I have seen here.  For more details try   
Hoffman et al.,  Lactose Fed-Batch Overexpression of Recombinant 
Metalloproteins in Escherichia coli BL21(DE3):  Process Control Yielding 
High Levels of Metal-Incorporated Soluble Protein. Protein Expression 
and Purification 6, 646-654 (1995).  Hope it helps.

Mike Rogers
mrogers at mayo.edu