  In this paper we continue our systematic analysis of the operatorial approach
previously proposed in an economical context and we discuss a {\em mixed} toy
model of a simplified stock market, i.e. a model in which the price of the
shares is given as an input. We deduce the time evolution of the portfolio of
the various traders of the market, as well as of other {\em observable}
quantities. As in a previous paper, we solve the equations of motion by means
of a {\em fixed point like} approximation.
