Bitcoin investments is a very promising investment which although seems to be of long term returns.most persons are not patient enough to wait till the value of Bitcoins rise significantly .
Soo in general how much should one invest in Bitcoin should it be "how much you can easily invest without stress " or "as much as you can invest at all cost"
Although I am aware it isn't a do or die affair
Invest any amount you can afford to lose, no significant amount is to big to invest in bitcoin and no amount is too small to invest, depending on the amount you are having, you don't have to invest all your money in bitcoin, it's wrong invest any amount you know it won't affect you even after investing, don't allow bitcoin investment to be a problem to you. Have seen people that want to sell their properties just because they want to invest, it's wrong nobody is forcing you to invest.
I agree with this, my first ever investment towards bitcoin was 20 bucks, as low as it gets, but I still had fun with it because it allowed me to spend it, back in those days transaction costs weren't this big, it was just couple cents, and that way I researched so much and learned so much about it.
I suggest the same to people, maybe 20 bucks to bitcoin isn't looking big now, but you could put it in an exchange, get something else, cheaper tx fee, and that way you could move it around and learn so much about it. This isn't going to hurt you because it's so low, and allows you to open the doors for so many things in the future and you should focus on that. Definitely a way to enlighten yourself about the crypto world.