Yes we are talking of FREE stuff. Robots uses electronic components. In our parlance it is about free component samples (ICs, LEDs, voltage regulators, relays, optoelectronic devices, and many more). There are companies which deliver product samples free to your doorstep. Not even mailing charges !! Yes it is true. But sometimes these samples are charged too. In such cases these are called 'samples' only because they can be ordered in a small quantities.
Also some companies have to be told as to what is your project and what you wish to do with the samples, so that they can guage their business prospect/potential. If they find you genuine, they send you the samples.
There are about 70 - 80 such companies I have heard of and about 6 - 7 of them I have tried and received samples from. I hope you are aware of all of them. In case you want something more, do wirte back to me.