Fourth Edition was one of the last sets to include the most basic cards with their original artwork, and that goes for basic lands as well
This new look includes a number of new cards and a handful of art variations, alongside the four commander cards we've already gotten a look at: Tidus, Cloud, Y'shtola, and Terra
The option to pay a spell differently is usually stated in the text of the spell (or ability suggesting an alternative payment) and appears as follows: You may [perform an action] rather than pay [this object]s mana cost This is stated on Force of Will or Shining Shoal, as well as in the rules for Flashback, Overload and Evoke
Omnath, Locus of the Roil Here, we have an Omnath design thats specifically an elementals build-around card
The grading question adds complexity: EX cards are genuinely worth grading here due to PSA 10 premiums on nostalgic designs, but submission costs require careful centering pre-screening