the SU-500 is an expensive organ that could be used at home but it is powerful enough for a hall or large building - I suppose it could be used in a church, but Lowrey's do not usually end up in churches.
You can store it in a dry place where mice cannot get inside it. The SU500 is a fantastic instrument that sold for a small fortune but the re-sale value of these instruments is not too great.
You can see them listed on eBay quite regularly - I think the last one I saw had a starting price of $14,000. Best thing would be to learn how to play it yourself and keep it!