Are you able to swap the box out by yourself? Then a box from the wreckers is a cheap option. There are 3 different auto boxes used in these cars, 1 the ZF, 2 Aisin Warner 4 speed and 3 Aisin Warner 4 speed with lockup converter.the two Aisin Warner boxes are interchangable, the ZF isn't. The Aisin Warner boxes are an upgrade for cars fitted with the ZF. It requires a few additional parts to make it work, but the results are good.

If you have the Aisin Warner box (also known as "the Toyota box" in Oz because its also used in Toyota's here) it is readily rebuildable. If you have a button on the side of your gear shift you have Aisin Warner box. The ZF is not worth the effort. Getting a wrecking yard box is fine but you need to get a guarantee that its a working box. My experience (here in Oz) is that most specialty auto wreckers want your return business, in a good way.

The best option if your swapping out boxes is to get the one with a lockup convertor. Note you can't convert a non lockup convertor box to lockup convertor. But you can swap a lockup converter box into a car that has the non lockup convertor box no problem.

Hope that helps.