What percentage of your weekly wage or net worth are you willing to kiss goodbye? That's the only metric that counts really. I started off with a couple of hundred quid and then went from there.
Are you looking for long term gains or do you want to get out rapidly with some profit?
The first priority of any investment strategy should be to maximize return while hedging against risk, thus there is nothing more important than protecting your capital.
From the lens of a new disruptive technology Cryptocurrencies such as Bitconi are barely scratching the surface. They are here to disrupt the traditional capital markets.
So you shouldn't invest more than what you can afford to lose but consider hedging against bad monetary policy with cryptos.
I remember, someone was telling that the bitcoin has become essentially a "religion" because people believe the values are assets and that is why the value appreciates. If one day the belief system collapses, the whole game will or would collapse as well.