$$\text{Their offer} = n \% \text{ of my offer, such that } $$

$$ \frac {n}{100} = \frac { \text {Their corporate domain wrecker price}}{ \text { My perfectly reasonable offer}}

$$

$$ \text{ Expressed as } \frac {n}{100} = \frac {\$ 5,000}{\$ 200}

$$

$$\text{ Thus, }\text{ } n= 2,500 \text{ ;}

$$

$$ \text{ Their price is } {2,500} \% \text{ }(n \%) \text{ of my offer.}

$$