Prices for Stars are highly variable. A 45 ACP machine with no case feeder sold on ebay last week for over $800. A 38 Special (Universal) with a case feeder sold a couple days earlier for $320. The same day the 45 ACP machine sold, a 38 Special tool head and shell plate sold for $400.
Personally, if it was mine to sell, I would want $400 for a 45 ACP Universal without a case feeder, $550 with a case feeder. A tool head with 38 special dies and shell plate should be worth about $300. Powder slides should go for about $25 each. Of course this assumes that everything is in good condition. I typically don't worry about a little surface rust, Stars usually clean up very well. You should get a look at the base below the shell plate. Machines that have been heavily used can develop a groove, and should be avoided. This is most common on machines that have been used with an indexer. Most Stars do not have this problem, but I have seen some that do.