Duolingo

Is pic related actually any good or just another "learn languages fast!" scam?

Good for the very basics, but you won't get to an advanced level thanks to it.

How can it be a scam? It's absolutely free

Ah, shit.

I took it as a game and got the very basics of german, I am on german classes while posting this and I recommend that (not browsing 4chin while in class) but to first practice in Duolingo and see if you like the language, then invest in real classes

can i actually learn to hold a conversation in a language with duolingo?

It can't help but at some point you will need real books with grammar and exercices to understand what's going on.

Not Duolingo exclusively

Second.
Nope. I already knew spanish, it only helped me. And the grammar is lacking too as well. The one thing I hate is that it often leaves pronouns in sentences,and sometimes marks you off for not having it, even when you rarely use them except for ambiguity.

Absolutely not, for the most part due to Duolingo's approach to grammar. In every lesson there's notes which explain grammar and shit but they are all skippable, which means you could complete the entire tree without being able to form your own sentences and only repeating what Duolingo tells you. This also leads to many people asking the same questions over and over again in the forums when they could just read the fucking notes instead
The other point is that Duolingo teaches you only a very small part of a language (I'd say A1/Lower A2)
All in all, learn grammar and use other sources