Where to get realistic stock data?

Question

Programming

I would like to dig deeper into exchange programming for dummies. Since the teapot is of purely theoretical interest. BUT I would like to work on the most real data.
So that not only stock quotes are, but also all overhead costs such as slippage, margins, etc. are taken into account.
Where there is a reliable source with free access and accurate emulation of the exchange game.

Answer 1

moex.com/a2193

Answer 2

Google api broker exchange
Here is https://www.instaforex.com/ru/client_cabinet_api

Answer 3

yes, forex