Capping supplements yourself doesn't require an encapsulation kit, though they are available and can speed the process up a little, they're often unnecessary, especially when you're not planning to cap hundreds. For this you'll only need capsules, a flat-bottomed bowl, and maybe some gloves if you really want.
The table below will show you which capsule sizes you will need for each nootropic. The weight was averaged out over 50 capsules made using the method below. Unifiram, Sunifiram, Coluracetam, and Noopept have been left out because the required dosages are far too small for available capsules and potential for error is higher. I can't recommend buying a set of jewellers scales enough, they're readily available from Amazon and are reliably accurate. Gem scales with an included tare weight are generally more reliable, you can pick them up for around $20/£20 here.
To get started you'll need a flat-bottomed bowl, capsules, and whatever powder you're planning to encapsulate. Smaller works better, unless you've got a large amount of powder (below I'm using piracetam).
Side note: I've found using enough powder in the bowl so it's roughly as deep/tall as the capsules you're using to be fastest. This method involves tamping the powder upside down, so the deeper the powder whilst still being able to hit the bottom of the bowl to compact everything, the better.
Separate the capsule, and hold the long half by the rounded end (see image below). Not too tightly, holding it by the more flexible upright walls will distort the shape of the capsule and when you let go, as the capsule returns to it's normal cylindrical shape, it'll disturb the powder and it'll fall out.
Now press the capsule firmly down into the powder, perpendicular to the floor, so the opening of the longer half of the capsule hits the bottom of the bowl. Keep pressing the capsule down into other parts of the bowl to compress the powder a little and make sure it's filled.
Now you can attach the shorter, stubbier, half of the capsule, and voila! Easiest way to encapsulate supplements!