SOA is not cheap. The springs may be cheap, but thats about it. You can HACK it together cheap i supposed.
You will need....
-Springs (stock YJs will work fine to get you by)
-New Shocks, $40 bucks each on average for something decent I wouldn't skimp out on shocks
-Shock Tabs, spring perches, possible u-bolts if you have to cut them $80 for new perches, $30 for new tabs
-CV drive shaft $250
-Slip Yoke Eliminator $280
-Track bar if you decide to run one and can't make it yourself $300
-Extended Brake Lines $100, PLUS you will probably be running new steel lines cause you break them trying to install the extended ones, then new slaves are a possibly too......
-STEERING everybody overlooks this, you will have to run a high steer setup, or maybe you can get away with reversing the tie-rod from under the knuckle and put it on top of the knuckle. If you can't make your own steering that is SAFE, steering kits get expensive quick, and are probably the highest cost/time consuming part of the build. Tera flex makes a cross over kit, as well as some other companies like Currie. Figure a steering setup will cost in the hundreds ($500-700 if you go with a complete kit from M.O.R.E. for example) as well.
My recommendation would be that unless you are going to plan on running a 37"+ tire i would just buy some really good SUA springs like 3.5-4" variety, get some TJ flares, and maybe a 1" BL, no shackle lifts. You can easily fit a 35" tire with that setup, at that point your axle strength will be in question though from the D35. You will still end up with a very capable rig that has a low COG, minimal wheel hop, and extra money left over for things like a roll cage, gears, lockers or whatever.
If you don't take the time to go thru the process and learn about your jeep before hoping right into some of the more advanced builds, you will lack basic skills as a driver, and people will get upset with you when little stupid shit breaks and you don't know what to do or how to fix it. Every man is expected to know his own rig, how it went together, and what its limitations are. Good Luck with your new toy