Ive got a No Claws package with 10 Astrea, 10 Nassarius and your choice of a sandsifting cucumber/brittle star/serpant star or you could sub out these guys for a ricordea polyp. Its 16.99 on the website.....should be plenty for ya.
Just say NO to blue leg crabs as they are considered aggressive toward snails and other crabs. You will be much happier with a no claws as suggested above or red leg crabs.