By default, you get one bonus attack when you take the attack action. The fact that you get two strikes now from a single attack action doesn't increase the number of bonus strikes that come with it.
So 3 by default, and 5 with a ki point.
Don't forget though that both your damage and your chance to hit are going up as well. Unarmed strikes now do 1d6 rather than 1d4, and proficiency mod goes to +3.
Edited: daishain on 5th May, 2017 - 3:48pm
Level 5. That's exciting ! I can't wait to see Geoffroy and Onwen hurling fireballs at the enemy! By the way I'll be taking donations to purchase a 300 gold piece diamond for revivify. Never worry about your character dying again! .
Edited: Kyrroeth on 5th May, 2017 - 4:03pm
They key on such things (And the source of much confusion among many players) are the key words Attack and Bonus Action. You'll often see 'Attack' capitalized because it represents your choice of primary action on your turn, along with options like Disengage and Dash. 'Attack' does not mean a swing of a weapon. The Attack action may mean one swing (Pre-level 5), two at level 5, etc. You'll never use Attack more than once per turn, unless you have Action Surge or something of the like.
'Attack' often grants some sort of off hand or unarmed attack, which is also often defined as a Bonus Action. Since you only Attack once per turn and only ever get one Bonus Action per turn, it is likely that you'll never get more than one unarmed strike with your Bonus Action. Flurry of Blows does up this to two unarmed attacks instead of one with your one Bonus Action via ki point.
My fighter in my other game usually swings twice with his primary weapon, or four times if I action surge, but either way still only swings his off hand rapier once per turn as my one Bonus Action. This is why forums will often tell you that the two weapon fighting style isn't optimized and doesn't scale well. I've obtained a great main hand weapon in that game and thus as I level I find the off hand rapier attack to be less and less important.
PS Obviously Daishain can tell me I'm wrong here and he's correct by default, just my experience.
PPS Thanks for the # of attack rolls explanation Daishain. That makes more sense now. Targul's # of rolls was a big contributor to my question.
Edited: Cinder on 5th May, 2017 - 4:03pm
She was probably thinking of resurrection, which does take a 1,000 gp diamond.
Difference between the twain: Revivify must be cast within 1 minute to work, with Resurrection you have a full century before it is too late.