Help with interfacing

I am finding I cannot find a good stitch-in interfacing in New Zealand. Is there any real benefit in using this or is iron-in just as good? The patter calls for the former but I cannot find it anywhere except online where shipping cost is too high.
Thanks guys!

zephyr

I did not know what interfacing was, but I think you mean the stuff you use between two layers of fabric?
Did you try already a Quiltstore?

I think they call it wadding or batting to? Just google.
I found the spotlightstores, here an example of one of the products, this is a cheap one, 150 x 200 cm $ 17.49, but they have many more.
They have 18 stores in New Zealand.

UPDATE ;P
I found the interfacing sew in, also in the spotlightstores
100 x 500 cm $6.29
They also have the iron in.