Those graded at a 9 or a 10 will be worth considerably more, but those in poor condition sometimes dont exceed the value of getting it graded at all
On reveal, Gandalf the Grey felt like an oddly colored card, lacking white mana to represent the character's fondness for peace, protection and benevolence, with Izzet colors representing reckless, creative innovation and experimentation
This deck has some interesting decision points and isn't a linear strategy, but it's also not the most complicated out there - and that's important for a beginner deck
Check for yourself: The three best tools are Cardmarket for a quick overview, eBay Sold Listings for rare special cases (e.g., serialized cards), and price lists/hotlists to see whats actually in demand
I will also take my time looking through Modern Masters sets