Is there a trading site that has a so called demo account? (Like most of the forex sites) Maybe it can be useful to learn in the beginning and after it can be done on a live account as well.
You can try avatrade.com
They offer demo account with free $100k to polish your skill. Take note tho that I have never tried it before so there is no way I can vouch for it.
Or, you can try signing up on yobit, after 7 days, you can collect free coins, just like collecting sat on faucets minus the captcha, and from there you can start trading the altcoins you have collected. This will take some time as you need to collect an amount equivalent to about 10k sat to be able to trade tho.
Alternatively, you can just deposit a small amount to any exchange or trading site you are most comfortable to use with and start trading right away with a meager amount while polishing your trading skill. You can move it up a notch higher when you have found your confidence.