The only place I can find that offers "
Linckia teres" currently has very few reviews that I can find, and all of them are terrible.
That said,
Linckia teres is not a valid taxonomic name, and the actual species in question is likely either
Linckia columbiae (also inaccurately known as
Tamaria stria) or
Echinaster luzonicus (the purple coloration isn't necessarily common for either species).
L. columbiae seems to be out of stock everywhere at the moment (it may be a seasonal thing, I'm not sure), but
E. luzonicus can be found from a number of different places, including a few that are reported to be more reputable:
https://seahorsesavvy.com/collections/starfish/products/neon-orange-luzon-starfishhttps://pacificeastaquaculture.com/products/burgandy-starfish