All you need to do is set up a couple of engine cards like Winding Constrictor, put some counters on a few keyworded creatures, and go to town from there
It is common for a description to sound like a high-rarity version, but upon looking at the photo, it is actually a different specification
A lot of balance and care goes into choosing the cost of a card, more than I can express here, but looking for similar effects on existing Magic cards can give you an idea of a fair costfor example, a ramp spell that puts two lands into play ought to cost 4 mana, per Explosive Vegetation
Just like any triggered ability, you're able to respond to cascade
If you can find one or two at a garage sale, or a stash in someones attic, it can amount to major profit
Designed for large trading card collections or organizational needs