"Be careful what you ask for"
A free sample of what?
Most Universities are pretty specific about what hardware they would teach on - not just the processor itself, but the demo board they want you to run your code on, so that their instructions are correct for your hardware. And they have probably done a deal to get a good price on those boards, with the manufacturer keen to see many more engineers familiar with their product rather than that of a competitor.
Oh and if you accidentally blew up the hardware the Uni did provide, speak to them. They probably have a few spares.
An stm32 microcontroller - even a high-performance one - is relatively cheap (sub 20 US dollars). They are made in huge quantities. But one is useless without a board to run it on, an interface to a PC to program it. And designing/making such boards is well beyond the scope of most Uni courses (as well as costing many times the cost of the mcu).
Demo boards can be much more expensive - they are made in small quantities, and might have several exciting peripherals - big screens, wireless transceivers, ...
But manufacturers do make cheaper demo boards - I think Bluepill is one. If that's beyond your budget, how can you afford all the computer hardware, interfaces and the like needed to do anything with the Bluepill?
For their products, the ST website has "sample and buy" which generally points you to a local distributor (who will want to be paid for what they supply) but where things are sufficiently new they might offer free samples. But they would do that with a view to selling many thousands of those parts in the future, so they might vet the person doing the asking. (Many years ago while I was at Uni, there was a computer manufacturer by the name "Sinclair". I had a friend who had that surname and he found it easy to get free samples from microprocessor manufacturers; I had no such luck when I tried).
Hope this helps,
Danish
