Vanette are a good source for an A15, you can get a whole car for a couple hundred if you look hard enough. Seeing that all 1200/1000 (and morris minor to a certain extent) owners aspire to put an A15 in their vehicles the price is pretty steap because they know threy'll get the price, which is a shame but that life!

Just keep an eye out, you can get a block that needs a rebuild for very little, a decent one be prepared to part with up to $500+

There was an A15 advitised on here not that long ago, it was mildly worked with twin carbs and extractors and some other goodies for $1000, it all depends on the purpose of the engine i spose.