The Internet is your friend, especially toy forums.
Check out the B/S/T threads.
Check the toy stores advertising in the sidebar.
eBay - for ML, DCUC toys, alot of those things don't have accessories. Check Chinese sellers on EBay. there are sellers that sell loose figures for quite cheep. If you are looking to backfill on missed toys, that's a good option. A good portion of my DCUC collection was bought from Chinese sellers.
Network. Make friends in other forums from the USA. I have a couple guys I buy from regularly. Since they are hunting anyway, I'll make a request and if they find it, they'll pick it up for me at a small mark-up for their time. This is where the other half of my DCUC collection came from.
also make friends with other collectors in your area. If you want something, voice it in the forums. Sometimes other guys find something and remember that I expressed it in the thread, so they'll hide it for me and pm me where they saw it. It is worthwhile to be nice and return the favour sometimes.
That said, check out the sightings threads.
