Where can i find a blue microwave?
Try checking out retro appliance and furniture stores online or in stores. Also a great source for finding specialty items surprisingly enough, is thrift and goodwill stores.
I've never seen one, but you could probably get one painted at an Autobody shop.
The store called "Target" sells blue, red , black and silver microwaves online or at their store and the price starts at $59 plus shipping and tax.