EggXpert

I'm cringing at the idea of buying a 15-20$ adapter kit for a SSD when I fail to see the need for it. The little beasties don't even have moving parts or anything. Couldn't you just lie them on a flat surface? Or strap them on somewhere with ties or screw them on the outside of the drive cage by two holes or something?

Essentially you are correct.  You really don't want something that can flop around in a case but as long as you are careful AND remember you have a lose drive you can absolutely leave it lose in the case, or secured by two screws...but this may present a shearing force if your case gets impacted or dropped onto a floor or other surface.  SSDs are money.

Kind of crappy it didn't come with a couple of adapter rails IMHO. 

I just noticed that the CoolerMaster Storm Sniper comes with an adapter, lets hope other case companines follow suit.  It is a nice touch.

Standoffs

I used AL hex standoffs. They’re cheaper and easier to install than brackets.

AL,#6-32x1/2"L; AL=6RU41 or Brass=6WA29 @ Grainger.

Wait, how do you screw into the standoffs? Do you mean they are the perfect length to convert from whatever it is (HDD) to whatever it is (SSD)?

You could build a DIY SSD tray using cable ties (whether you use the plastic, zip-type or velcro). With the zip type, you could probably weave something like a hammock; it doesn't even have to be solid, maybe three or four across. Then add a few at the back to keep it from sliding off if the case is moved, and finally add a similar amount on top of the drive, just enough to keep it from moving, but not tight enough that you can't pull the drive out.