Ghyrson Starn, Kelermorph : Around $22 Shadow in the Warp : Around $17 Exalted Flamer of Tzeentch : Around $17 Keeper of Secrets : Around $15 Bloodthirster : Around $15 And They Shall Know No Fear : Around $13 Celestine, the Living Saint: Around $10 Resurrection Orb : Around $10 Biophagus : Around $10 All images via WotC
Banding allows any creature with banding, and at most one creature without, to attack in a band. The band can be blocked by any creature that could block a single creature in the band
Lobelia Sackville-Baggins, by Hristo D
Bria, Riptide Rogue Bria, Riptide Rogue is a neat little card
Wheel and Jar on the other hand are just a bit too much, you need to put in too much effort in building around them to make them viable inclusions
The ideal way to estimate the value of Pokmon cards is to consult resale platforms between private individuals and/or professionals (called "Marketplaces" - for example: eBay or TCG Player) and analyze the resale values for each card you wish to estimate