Evolving Wilds

This and Terramorphic Expanse can give you the feeling of having the expensive sac-lands in your deck without you having to spend more money than you are comfortable with.
The reason why these lands are good, is because they can help you get the right kind of mana when you need it, they trigger Landfall abilities, and they thin your deck for lands.

As a new player, I could not understand why thinning my deck of lands was a good thing, but then I learned: playing an Evolving Wilds or a Terramorphic Expanse basically means that you'll be removing 2 lands from your deck (the Terramorphic Expanse/Evolving Wilds + the basic land you searched for). The reason why this is good, is because it lowers the chance of you drawing excess lands, and increases the chance of you drawing non-land cards when you need them. Imagine if you're playing 8 Terramorphic Expanses and Evolving Wilds in the same deck, and you get them all out and have used them by your 8th turn - by your 8th turn, you've actually removed 16 lands from your deck, which means that you'll be a lot less likely to draw excess lands, and have much higher chance of drawing the spells that'll kill your opponents.

The only problem with Evolving Wilds & Terramorphic Expanse is that the lands you search for enters the battlefield tapped, meaning that you normally won't be able to use it before your next turn - however, Amulet of Vigor solves that problem. :)

A Diligent Farmhand for every deck. Use wisely :P

If you do not have fecthlands!!