Good place to buy altcoins for newbies are binance and kucoin.Those two are very easy to us, the UI is simple and no need for complicated signing up and verification.
The current scenario Binance and kucoin is a good exchanges but Binance is best for all the trading. The current market is really unpredictable so newbies are carefully choose the best coin in this situation. Because altcoins are really bleeding in recent days but right now all are green in the market. So we can't predict the exact outcome in future results and this will be useful for many beginners in this forum.