The cheapest thing you can do to improve body roll is to replace all four sets of sway bar end link bushings. I do recommend poly bushing here as you do want them stiff, these 4Runners have a lot of body roll once they age. I'll list some other low-cost things to improve on-road handling (I consider my 4Runner an on-road build):
Sway bar end link bushings - $30. Energy Suspension sells a good kit that works well.
Sway bar bushings front and rear - $30. Once again Energy Suspension has good kits.
Steering rack bushings - Stick with rubber. New bushings help with steering slop but poly bushings will transfer vibrations from the front wheels to your hands while driving. They are difficult to replace though.
Shocks - OEM Tokico blacks are the smoothest on-road shocks you can buy. Same goes with OEM springs like the 99 talls. Almost every other aftermarket shock and spring is made for offroading in mind, not on-road driving. Rear OEM Tokico's can be had for $42 each:
Shock Absorber - Toyota (48531-80693) | Toyota Parts.
I would save the money and not buy the Addco sway bars. The bushings alone will make a huge difference.