For the cost of X, Marath allows you to remove that many counters from it in order to utilize one of three effects one of which happens to be to create an X/X Elemental token
The most common iteration will use Team Rockets Handiwork so that we can start aggressively milling our opponent
This card deservedly hovers around the $100 mark in LP condition, as NM copies are very difficult to find and rarely sell on TCGplayer, as they're usually graded when they're clean enough to be considered NM
Interstate permit and hill station charges are extra where applicable
Every Goblin can just pay for another Goblin and turn a profit
The final bit of text reads: If a legendary permanent or an artifact entering or leaving the battlefield causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time. Basically, Gandalf the White can do a lot of good stuff, and being a 4/5 isnt bad either