All they are (mini-FM tuner) is some copper coiled around a metal bar, a battery, a variable transistor and a few more transistors...
I mean, your TFT monitor has 3 transistors for every pixel. Assuming a (slightly low) 1024x768 'native' resolution, that's 2,359,296 transistors in your monitor.
So they're quite cheap anyway.
...Although you are right, you wouldn't earn a lot making those things... Most of the cost would be taken up by shipping, the profit added by the shop itself & the parts in the first place.
16-colour PNGs pwn.