As many as you want... But each is Approx. $22.5 per account.
As of the date of this answer, over 42 million people have created accounts on minecraft.net, the game's website, and over 8,293,494 have upgraded their accounts to premium and bought the game.
There is no limit.
as of may 11, 2013, 10,450,125 minecraft accounts have been purchased.
Yes, you can log into as many minecraft accounts on one computer as you want.
Yes, you can make as many accounts as you want free, but you pay for the download onto your computer. (I actually asked this Q, but I've been searching and you can!) :P :D
Because minecraft is an AWESOME game.
No, many people are using minecraft without any problems with viruses.
3
You can make as many accounts you want to. There is no limit or end to that. However if you make many accounts with same information, they might be blocked.
You can log into the Minecraft launcher on one PC with as many accounts as you want. You can also install as many as you want on each computer you have. However your saved games are not syced between PCs. On the same PC though, each launcher will still be able to access the same saved worlds.
22357673 and increasing
over 8,374,342