The custom fit sun shades from Weathertech aren't cheap (~$50) but they are an exact fit. I don't have one for my 4Runner since I park in the garage but I do have ones for the other vehicles in my household and they all fit very nicely. Buy once, cry once.
WeatherTech | Custom Fit Car Mats, Floor Mats, Trunk Liners, Window Deflectors
I have been using this one for the past two years. Very good quality.
Amazon.com: Covercraft UVS100 Custom Sunscreen | UV11140BL | Compatible with Select Toyota 4Runner Models, Blue Metallic: Automotive
Had one of these for my 4th Gen, and now have one for my 5th. They work very well.
I just spent $150 to have my windshield done in XPEL ceramic "tint" (went with the clearest possible), and highly recommend a UV layer versus a sun shade you have to bother with.