What you are asking for is more of purchasing problem than anything technical. You can buy standard surface mount oscillators for less than $1/each if you search hard enough for the right supplier.
Even Digikey has some. For example, Digikey Part #535-9777-2-ND is 100 MHz and US$0.966/each in 1000 piece qty. There are others, too. As a very rough rule of thumb, Digikey is 30% higher than going through a normal distributor. With some leg-work you could probably find a canned oscillator around 200 MHz for less than US$1.
You could also go cheaper by getting a basic crystal and building an oscillator with it and a couple of inverting gates (and some passives). Google will show you many schematics for this sort of thing. But even here, it is more of a purchasing problem than technical as you would generally design your circuit after you find the crystal.
Update: You added the stuff about sine waves after I wrote my answer. Oh well. Look for more RF specific oscillators, since they tend to be higher frequency with sine wave outputs. But I'm not that familiar with what is available for RF.