Answer
500 paper plates for $8.99 is the better buy.
Work Step by Step
100 paper plates for $\$$1.98 --> $\frac{\$1.98}{100\text{ paper plates}} = 0.0198 \frac{\text{ dollars}}{\text{ paper plates}}$
500 paper plates for $\$$8.99 --> $\frac{\$8.99}{500\text{ paper plates}} = 0.01798 \frac{\text{ dollars}}{\text{ paper plates}}$
0.01798 < 0.0198
