where can i advertise my website..on the internet for low cost? have yahoo & google?

where can i advertise my website..on the internet for low cost? have yahoo & google?

i owned and operated a small cleaning services residential & commercial
i need clients and need to advertise my website and dont know how to do it or where...i only know yahoo and google but how much do they charge you?? any ideas or suggestion will be very apreciated. thank you Marie.. Charleston, SC