hello,
is it worth to invest in automatic trading bot for trading altcoins at exchange sites?
thanks

They are.
If you buy Gunbot is have little risk of losing money because it has an auto algorithm.
I think that it is definitely a good one to get if you have starting capital, however ifg you only have like 0.2 BTC anyways and you want to get a bot that costs 0.1 BTC, you're probably not going to achieve ROI.