When I try to plot this:
\begin{tikzpicture}
\begin{axis}[%
scale=1.5,
max space between ticks=25,
ticklabel style={font=\scriptsize},
axis lines = middle,
xmin=-8000, xmax=9000,
ymin=-10000, ymax=130000,
domain=-8000:9000,
grid=both,
xlabel=$ q $, ylabel=$ R\ C $,
yticklabel style={
/pgf/number format/fixed,
/pgf/number format/fixed zerofill}]
\path [pattern color=yellow, pattern=north west lines] (axis cs:8000,-10000) -- (axis cs:8000,130000) -- (axis cs:9000,130000) -- (axis cs:9000,-10000) -- (axis cs:8000,-10000);
\addplot [very thick, blue, smooth] {15*x};
\addplot [very thick, green, smooth] {5*x+30000};
\draw [fill=red](axis cs:0,0) circle (2.5pt);
\draw [fill=red](axis cs:8000,120000) circle (2.5pt);
\draw [fill=yellow](axis cs:3000,45000) circle (2.5pt) node [below right] {$B.E.P. (3000,45000)$};
\draw [fill=red](axis cs:0,30000) circle (2.5pt);
\draw [fill=red](axis cs:-6000,0) circle (2.5pt);
\draw [thick, red, dashed] (axis cs:8000,130000) -- (axis cs:8000,-10000);
\end{axis}
\end{tikzpicture}
I get this diagram:

which has a scientific notation on y-axes, and I don't want it. How can I avoid this lack?
