A model for the average price of a pound of white sugar in a certain country from August $1993$ to August $2003$ is given by the function

S$($t$)=0\mathrm{.}00003237$t$5+0\mathrm{.}0009037$t$40\mathrm{.}008956$t$3+0\mathrm{.}03629$t$20\mathrm{.}04477$t $+0\mathrm{.}4898$

where t is measured in years since August of $1993.$ Estimate the times when sugar was cheapest and most expensive during the period $1993-2003.($Round your answers to three decimal places.$)$