It's important to read "counter" in this instance because while she may only provide +1/+1 counters herself, there are a lot of counter types in the game
So then the question becomes, for two mana, would you play a card that gives you a Treasure when an opponents creature dies once each turn
Add in the low supply of many Reserved List cards (which occasionally allows sellers to manipulate the headline price number by listing a copy at an unrealistically high price point, which is how we ended up with Moat at $100,000 this week, even with a BSG 9.5 copy for sale at $3,400 and a played copy at $1,500), and the headline price of a card tends to overstate the price that you can actually get the card for, if you are willing to lower your standards a bit
(#113/108), reprinting the original Team Rocket expansion trainer card, has built a small dedicated collector following
Radstorm (21k, $3 to $25) The long-term outlook on this is great, especially because proliferate works in a wide variety of decks
These lands were groundbreaking when Unhinged and Unglued came out, but we've had two editions of Zendikar since then along with random full-art promos from other sets