how does "your shop" determine what to give you?

because there are like 3 different things i wanted and "my shop" isnt giving me anything i care about at all in fact my 60 and 70% discount are on champion i haven't even played once in a pvp rift game.

and only 2 of my "discounts" are on champion i actually even PLAY.

how is these even determined?

i mean it clearly knows they TYPE of champions i play as as they are all "mage type champions"

but.. Im not going to buy a skin for a champion if i dont play the champion.

close riot... but unfortunately... not close enough.