Kozilek, Butcher of Truth unfortunately doesnt have the fun (and annoying) ability to counter your opponents spells
Its maybe not as popular as it once was, and other versions of the card are around the $8 mark, so I dont expect it to get too high
You could build a Dimir Vehicle deck, but I think they are much better in the 99 of some other commanders on this list
Chart shows the price of Rikku, Resourceful Guardian #41 at the end of each month going back as long as we have tracked the item.
HIGH-QUALITY MATERIAL: These card sleeves feature strong welding for durability to prevent bent corners, scratches and damages from shuffling
Seriously, using this with unleash cards or other ways to slap those +1/+1 counters onto your creatures is going to be incredible powerful