I had the same issue.
So first your compile one pdf file containing only one business card. Then you need to compile another file that produces 10 business cards on a a4 page (5x2 matrix) the code is.
\documentclass{article}
\newcommand{\verticalcards}{5}
\textwidth 22.00cm % 21.59cm
\textheight 27.94cm
\topmargin -1.75in % was -1.0
\headheight 0in
\headsep 0in
\oddsidemargin -0.5in % ok fits A4 paper
\usepackage{pstricks} % allows using PSTricks!! Remove if you don't have it.
\usepackage{pst-node} % nodes in pst
\usepackage{graphics}
\pagestyle{empty} % removes page numbers
\begin{document}
\noindent
\setlength{\unitlength}{1in}
\begin{picture}(8.5,11)(0.0,0.3937) % revised for 5 vertical per page
\thicklines
\multiput(0,0)(3.64,0.0){2}{ % horizontal (x) motion
\multiput(0,0)(0.0,2.14){\verticalcards}{ % vertical (y) motion
\framebox(3.5,2){ % x,y size of box, inches
\shortstack[1]{
\includegraphics*{BC/qrGrey.pdf}
} % end shortstack
} % end makebox
} % end multiput
} % end multiput
\end{picture}
\end{document}
I compile my single business card with xelatex. However, I compile the previous code with pdflatex. Of course, you need to change "BC/qrGrey.pdf" with your own file.
I just show the output with a zoom out to show you that it's working (5x2 cards on a4 page)

\documentclass...until\end{document}. – masu Jan 13 '14 at 15:15