The Dragon adventure Wells of Darkness also contains planar fork price suggestions.The only time I have seen this adressed is in the Green Ronin module "Hell in Freeport." It states that in order to Plane Shift out of Hell, you need a tuning fork attuned to the Prime. Since only the most powerful devils can voluntarily exit Hell, these forks are virtually priceless. After all, what Devil wouldn't want to ravage the Prime?
I think this is true of most of the Lower Planes as well.
As to going in the other direction, from the Prime to other planes, I'm not sure.
That would be Dungeon Magazine 148, p.57.The Dragon adventure Wells of Darkness also contains planar fork price suggestions.
Particularly common in the Broken Reach marketplace are the metal rods used as material components for plane shifting to different layers of the Abyss. Rods for relatively well-known layers such as Pazunia, the Demonweb, Gap-ing Maw, Thanatos and Shendilavri sell for 3,000 gp. Rods for more obscure lay-ers, such as Twelvetrees, Shedaklah, and Androlynne sell for 9,000 gp. Rods for truly remote realms, such as the Dreaming Gulf, the Blood Shallows, or Zionyn sell for 15,000 gp. Certain rods are particularly rare, as the Abyss itself allowing travel to its deepest and most important layers. This includes layers such as Ulgurshek, Woeful Escarand and the Wells of Darkness; these rods cost 40,000 gp apiece.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.