The C-store Needs reputable sale items are I fear the game will die. Limited Edition Items may be the way to go. You cant use a cannon type item BUT A never before seed ship skin, Limited Dress like one from Forbidden Planet 1952. would work well. Limit them to only 5000 once you sell you cant get them anymore.
This could be sold per character because they are limited. As long the C-Store is upfront about it. Price need to be about 1$USD in C-Store credit. You could not use something like kirk green shirt from season two but there tons of shirts that could be use. Limited Editions Items could have Star Trek theme but you could not use anything from the the TV/Movies.
Pets again Limited Editions. Holo pets would be fair game. Max of 5000. The list could get long here. Dragons, 6 legged cats, This could go on forever.
Two or three items could be added each patch. Once they are gone they are gone.
Last make a sing up list. So the People how want them would get a e-mail once they hit the C-Store