Almost every single city I know of has a law that does not allow roosters inside city limits. And some cities require not more than 3 hens.
Best thing you can do is probably call your agricultural department or zoning/code enforcement and ask some questions.
If you've never dealt with roosters before... Silkies can be just as much jerks as any other boy, just in smaller packages. That doesn't mean it doesn't hurt when they bite. If you go in knowing you can't keep all of them, then maybe you prepare yourself and let them go to someone else's dinner table?
They often wanna know what you are going to do with the waste.
Also, you won't "make" $10/chick. you gotta get an incubator or let your hen sit, during which time she won't lay eggs. Then if you take the chicks when they hatch to sell... that's kinda cold blooded. If you let her raise them... everybody can tell who the boys and gals are and nobody wants boys. And if using an incubator... there's power, maybe time turning, not really 100% hatch rate, heating lamps or pads and brooders plus shavings and paper towels, vitamins, and chick feed... until buyers arrive. Being able to CULL the chicks that hatch with deformities. The pacing during hatch, trying to get the humidity right and be home to check things. No vacation. The never ending hours of research. Maybe vitamins and higher quality feed for the parent stock. Predator loss. Power outage might cause hatch failure or many deformities. Cost of the egg itself. Fertility rate. (I feed all my infertile eggs back to the animals so they aren't wasted). Rubber shelf liner for the hatcher. Housing and original stock and rearing costs are also factors.
It's a process is my point, and there are many factors that should be taken into account, including local feed price and LOCAL MARKET. I offer to take back males as a community service (for free) with the understanding that they will become food for my family and pets or someone else's and not returned to my flock. This allows for buyers who otherwise could by them sexed at My Pet Chicken for the same price and don't have the willingness or ability to process themselves or keep boys. Majority of people where I am will process their own birds.
Silkies are popular and seem to sell easy. Give it a try if you wanna have some fun... but don't plan on getting rich quick. Even at that price, I find it's still a labor of Love.