Tough to say, as Mermaid says they were and I think are on continual release I think; always turning up in various and different packaging.
I am dredging the memory banks but I think Party is right and late 90s-ish but its always possible they were released again later or currently in the same style/packing. You may have more luck trading then selling. But if selling $2-3 sounds feasible.
And I am loving your signature and avi - the flower suits Sunset perfectly!