cheapest, best way to add 1-2" and slightly stiffen my suspension...

Hoping for help finding the cheapest, best way to add 1-2" and slightly stiffen suspension on my 2009 Tacoma Extended Cab with FlipPac camper on back. It's got new Billsteins on it but still is bottoming out when even moderately loaded for camping trip and squishy up front. Can't afford to spend tons and don't want it to be too stiff. Thanks for any and all help.