I don't see what advantage there is over packs rather than cards. My approach has been to stack individual, uncombined cards rather than packs.

Especially summoners. I think I've got around 50 Beta summoners uncombined. I'm sure that's where the money is. I've got a fair few dozen cheap regular and gold cards too, typically the ones everyone uses all the time.

Then again I kind of wish I had a few Betas.

That's a lot of matches you've got to play to get that DEC!