Honestly, IMO i find it pointless to buy live rock if your tank isn't already cycled. Cured or non-cured. I know i've heard stories of people cycling with live rock and still have life left on the rocks after cycling, but that isn't always the case. Too much rock will produce too much ammonia. Too much ammonia kills everything. That's what happened to me :/
My suggestion would be to just get as much base rock as you want, set it up in your tank to your liking and then just cycle with a shrimp. This way you can actually control your ammonia levels by putting either a large piece or a small piece and adding or subtracting the shrimp if your not getting any spikes, or enough ammonia to start up a good cycle. After you tank is cycled, all you really need to do is get a few pounds of cured live rock and throw it in your tank(not literally lol). This will start the seeding process of making the base rock in the tank "live" once again, and honestly, you begin to see things within weeks. For the base rock to become fully live and thriving it will take a good amount of time, but you will start seeing life within the first couple weeks. My tank went through an ammonia nuke(well over 9ppm) because i had too much uncured live rock with mass die-off and everything started decaying pretty quickly. However, when my cycle was done and i added 3lbs of live rock, about 2 weeks later i was seeing little reef bugs ALL over the rocks and the sandbed throughout the entire tank. Didn't take very long at all. I also saw many other things besides the reef bugs. It was pretty crazy.
If your looking for a cheap solution, you may just want to go with base rock first. That's what i will be doing for my next tank.