Before you get Rhino lining, spray water in your truck bed & try to walk around in it in sneakers, be careful, you'll crack your head open when you fall.
I got Line-X this time.
Also, the doggone spray in liners are 3-4X the cost of a drop in liner, if it's an older truck, or one you don't plan on keeping for a long time, get the $99 dollar special drop in liner...