Hi Michael,
I recently purchased a very nice Japanese ume from Bella Bonsai for under $200. Here's the website... and looks like it's still available:
Japanese Plum Bonsai Tree for sale at Bella Bonsai Nursery
bellabonsai.com
The tree arrived very healthy with lots of small flower buds. It's been left outside for the past couple month (I live in Queens, NY). Although it's not as lush green as when I first received it, I'm quite optimistic and the buds are all still there. Looking forward to seeing it bloom hopefully soon.
Gloria