You can buy sight paint that's pretty decent. What kind of handgun do you want it for. Colored front sights are available for Ruger revolvers and are easy to change out. I'm not sure about other brands.
“If ye love wealth better than liberty, the tranquility of servitude better than the animating contest of freedom, go home from us in peace. We ask not your counsels or arms. Crouch down and lick the hands which feed you. May your chains set lightly upon you, and may posterity forget that ye were our countrymen.” ― Samuel Adams