I was looking for micro stars a while back also.
Could not find anyone who sold them locally.
Problem is they hide in tiny cracks and are hard to get out. If you tried you'd just end up with a bunch of arms.
MCF may be your best bet. Although I went there and asked if they sold the micro stars 6 months ago, and they said they didnt. They receive them all the time with shipments of liverock, but never kept them. Probably assumed noone wanted to buy them.
Also, the same with acro crabs. They told me they came in on corals, but they never bothered keeping them. I want to buy a bunch of acro crabs.