I bought a similar light from Target.. and returned it. I didn't consider that I'd have to remove the light in order to use the cover. Too much hassle for me. I prefer the lighted Kindle cover so I have it all in one neat package.
The Amazon link you reference specifies 1 AA battery. The
Octovo page also confirms one AA battery.
Edit: looking at the pics of the Solis, it looks like a very simple clip attachment.. which appears very easy to attach/detach. Looks pretty good to me... and it should for $30.