Effectively, for each card you spend, you get one to replace it
Your Store Championship can be a taste of competitive play for your community, leading into larger events like Regional Championship Qualifiers
Similarly, Clandestine Chameleon will lose abilities as those stickers are removed or those permanents and/or cards go to zones other than the battlefield or graveyard
However, secretly, the card that stole my attention was Skyshroud Lookout
You can fill the rest with cards you already own to reduce the cost of your deck even further
Rather than a static buff to their stats, it grows these creatures types with +1/+1 counters whenever you gain life, which is pretty big game because, by and large, most of these creature types tend to start rather small