Yeah, you can get away with a really nice but pretty cheap system by using the
Thule 554XT surfboard rack on your 1998 Toyota 4Runner roof rack crossbars. The 554XT includes everything you need to strap on up to two surfboards. You would need to attach a second 554XT setup to the crossbars if you wanted to carry 3-4 surfboards at once. Also I would suggest using either
Lashlocks or
SteelCore strap locks to lock your surfboards to the rack if you ever plan to leave them unattended.
There is another superior surfboard rack system if surfboard locks are a big concern for you. It's from Inno Car Racks and called the
BoardLocker surfboard rack. It also mounts directly to factory roof rack crossbars. The locks are integrated right into the rack system itself. The only drawback is it's somewhat pricier than the cheaper Thule 554XT Hang-Two surfboard carrier suggested above.