AMC 12 2005b Problem 1

A scout troop buys $1000$ candy bars at a price of five for $2$ dollars. They sell all the candy bars at the price of two for $1$ dollar. What was their profit, in dollars?

$\mathrm{(A)}\ 100 \mathrm{(B)}\ 200 \mathrm{(C)}\ 300 \mathrm{(D)}\ 400 \mathrm{(E)}\ 500$