Lisa decides to work at a hair salon as a hair stylist. She is required to pay $$100$ per month to work at a station. She earns $25\%$ of her customer's cost of services. The total amount $(y)$ that she makes each month on $x$ cost of services is given by which of the following equations?

$y=100x+0\mathrm{.}25$

$y=0\mathrm{.}25x+100$

$y=-100x+0\mathrm{.}25$

$y=0\mathrm{.}25x-100$