First Problem
Removing a huge load of unneeded packages, your document now compiles fine. I also added some extra things, like \begin{figure}...\end{figure}.
Implementation
Compile with xelatex or latex -> dvips -> ps2pdf
\documentclass{report}
\usepackage{pstricks-add}
\usepackage{pst-poly}
\begin{document}
\begin{figure}[!htb]
\centering
\begin{pspicture}(0,0)(5,3)
\psgrid(1,1)(0,0)(4,2)
\end{pspicture}
\caption{Figure 1}
\label{fig:pst1}
\end{figure}
\begin{figure}[!htb]
\centering
\begin{pspicture}(0,0)(5,3)
\psgrid
\end{pspicture}
\caption{Figure 2}
\label{fig:pst2}
\end{figure}
\begin{figure}[!htb]
\centering
\begin{pspicture}(0,0)(5,3)
\psgrid(1,1)(0,0)(4,2)
\end{pspicture}
\caption{Figure 3}
\label{fig:pst3}
\end{figure}
\begin{figure}[!htb]
\centering
\begin{pspicture}(0,0)(5,3)
\psgrid
\end{pspicture}
\caption{Figure 4}
\label{fig:pst4}
\end{figure}
\begin{figure}[!htb]
\centering
\newcommand{\sides}{6}
\begin{pspicture}(-3,-3)(3,3)
\providecommand{\PstPolygonNode}{\psdot[dotsize=0.15](1;\INode)}
\PstPolygon[PstPicture=false,PolyNbSides=\sides,unit=3]
\end{pspicture}
\caption{Figure 5}
\label{fig:pst5}
\end{figure}
\begin{figure}[!htb]
\centering
\begin{pspicture}(4,5)
\psframe(0.7,2)(3.3,3)
\rput(2,2.5){First Example}
\end{pspicture}
\caption{Figure 6}
\label{fig:pst6}
\end{figure}
\begin{figure}[!htb]
\centering
\begin{pspicture}(-1,-1)(5,5)
\psaxes{->}(0,0)(-0.5,-0.5)(4.5,4.5)[x,0][y, 90]
\psdot(2,1)
\uput[0](2,1){A}
\end{pspicture}
\caption{Figure 7}
\label{fig:pst7}
\end{figure}
\begin{figure}[!htb]
\centering
\begin{pspicture}(0,0)(5,3)
\psgrid(1,1)(0,0)(4,2)
\end{pspicture}
\caption{Figure 8}
\label{fig:pst8}
\end{figure}
\begin{figure}[!htb]
\centering
\begin{pspicture}(0,0)(5,3)
\psgrid
\end{pspicture}
\caption{Figure 9}
\label{fig:pst9}
\end{figure}
\end{document}
Output (Just the first page)

Second Problem
God only knows, why there was a figure in the preamble...
Implementation
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc,decorations.pathreplacing}
\begin{document}
\begin{tikzpicture}[domain=0:5,scale=1,thick]
%Define linear parameters for supply and demand
\def\dint{4.5} %Y-intercept for DEMAND.
\def\dslp{-0.5} %Slope for DEMAND.
\def\sint{1.2} %Y-intercept for SUPPLY.
\def\sslp{0.8} %Slope for SUPPLY.
\def\pfc{2.5} %Price floor or ceiling
\def\demand{\x,{\dslp*\x+\dint}}
\def\supply{\x,{\sslp*\x+\sint}}
% Define coordinates.
\coordinate (ints) at ({(\sint-\dint)/(\dslp-\sslp)},{(\sint-\dint)/(\dslp-\sslp)*\sslp+\sint});
\coordinate (ep) at (0,{(\sint-\dint)/(\dslp-\sslp)*\sslp+\sint});
\coordinate (eq) at ({(\sint-\dint)/(\dslp-\sslp)},0);
\coordinate (dint) at (0,{\dint});
\coordinate (sint) at (0,{\sint});
\coordinate (pfq) at ({(\pfc-\dint)/(\dslp)},0);
\coordinate (pfp) at ({(\pfc-\dint)/(\dslp)},{\pfc});
\coordinate (sfq) at ({(\pfc-\sint)/(\sslp)},0);
\coordinate (sfp) at ({(\pfc-\sint)/(\sslp)},{\pfc});
% DEMAND
\draw[thick,color=blue] plot (\demand) node[right] {$P(q) = -\frac{1}{2}q+\frac{9}{2}$};
% SUPPLY
\draw[thick,color=purple] plot (\supply) node[right] {Supply};
% Draw axes, and dotted equilibrium lines.
\draw[->] (0,0) -- (6.2,0) node[right] {$Q$};
\draw[->] (0,0) -- (0,6.2) node[above] {$P$};
%Price floor and ceiling lines
\draw[dashed,color=black] plot (\x,{\pfc}) node[right] {$P_c$};
\draw[dashed] (pfp) -- (pfq) node[below] (qd) {$Q_d$};
\draw[dashed] (sfp) -- (sfq) node[below] (qs) {$Q_s$};
\draw[->,baseline=5] ($(0,{\pfc})+(-1.5,0.7)$) node[label= left:Price Ceiling] {} -- ($(0,{\pfc})+(-.1,0.1)$);
\draw[decorate,decoration={brace,mirror}] (qs.south) -- node[below] {some text} (qd.south);
\end{tikzpicture}
\end{document}
Output
