As much as you can afford. I believe in bitcoin and it's capacity to grow. I usually use it as my hedge fund.
Yes, I agree. In investment, you can invest as much as you want, it all depends on your strategy. If you want to earn a big profit, then go for a big investment but be sure to follow the correct and right strategies so you wont regret in the future.
There is no minimum amount you can invest in Bitcoin. You can invest almost any amount you want. You can buy a fraction of Bitcoin as well. Buying a fraction gives you exposure to the market and helps you for the next intake in the market. Besides, this is the beauty of the technology that gives you the freedom to invest any amount in the market and earn from the comfort of your home.