I have heard Signets are pretty good. *hides*
I am not sure what you are asking. At what mana cost do you consider something cheap? I mean, outside of Elves at 1 CMC, you have
Wild Growth/
Utopia Sprawl, which are fine I guess, but don't really provide the same dynamic as elves (able to be killed, sacrifice fodder, chump blockers, etc) so seem pretty boring. I guess if you have some sort of 'enchantments matter' theme, then they could be cool. I really like
Search for Tomorrow. I know that the land coming in untapped is the same as casting a
Rampant Growth on turn 2, but it feels so great when you get to put it down untapped. I have no experience with
Fastbond, but I am sure someone will be along soon to tell me about awesome things it does. If you want to read a card which is crazy edge-case, but might have some real play to it, check out
Manabond.
At two,
Farseek seems far and away the most flexible of the
Rampant Growths, as fetching dual lands is pretty awesome.
Sakura-Tribe Elder has a bit of play to it (when, by play, I mean, it blocks something once).
Explore is a cool effect. Then you have all of the artifacts, but I am sure you are across those.