It is all upside when you have plenty of extra mana, though
Youll find a mix of cards going for way more than the reasonable asking price, but also the occasional steal where someones asking for less
Phantom Nishoba Loxodon Hierarch Nazahn, Revered Bladesmith Qasali Pridemage Saffi Eriksdotter Mystic Enforcer Knight of the Reliquary Fleetfoot Panther Gaddock Teeg Voice of Resurgence Rhys the Redeemed Tolsimir Wolfblood Wilt-Leaf Liege Sigarda, Host of Herons Sigarda, Heron's Grace Selvala, Explorer Returned Selesnya Guildmage Renegade Rallier Armada Wurm Captain Sisay Centaur Healer Dauntless Escort Dromoka, the Eternal Dragonlord Dromoka Enlisted Wurm Fleecemane Lion Karametra, God of Harvests Kitchen Finks Loxodon Smiter Mirri, Weatherlight Duelist Novablast Wurm Holy crap
Even better will be the things that spike as a result
For new players, the best booster products are simple, useful and easy to play with