-Car-part.com -lists places that have it by zip code you put in
-Check local junkyards
-E-bay has tons of used car parts just go with someone reputable.
-You can also try Facebook marketplace and Craigslist for folks parting out a 4runner.
I've used all of these but E-bay is probably the one I go to the most for used parts as it is easy and mailed right to you.