Carlson's brand is the one I started with. If you get their brand try the whole 5 mg capsule the first time with a teaspoon of coconut oil or olive oil. Then you can start breaking the capsule open and take half in the morning and half at night. do not leave the contents exposed to light for too long as it will deplete K2's potency.
A better buy will be 90ct 15 mg caps from pureformulas.
You can see that by breaking the caps open, it makes a good deal.
Occasionally VRP will have their K2 mk4 for 26 dollars a bottle but you have to buy 99 dollars worth to get the deal. keep your eyes peeled for their 50% off deals.