If you dont have the money for everything now, then do the springs and shocks at a diffferent time than the sways since they aren't tied in with similar labor or anything like that.

Like AccordSleeper said, the labor for installing the springs or sways is exactly the same, so you can pay for labor(~$150) once and do both at the same time or do it separately and pay the labor twice.

Also if you are afraid of a harsh ride, getting the adjustable shocks will let you fine tune the ride making it harder/softer as you like it, so take that into consideration also.