It is the violet purple one. It had just finished blooming. Was on clearance.
Is this a common one?
does it have the hybrid name tag with it?
Maybe one of the thumbnails in the link might look like your orchid? Many species and thousands upon thousands of hybrids make an id on colour impossible.
Here is a link that might be useful: Dendrobiums & a few Dockrillia
No, no hybrid tag.
No, none you have photographed appear to be the one. The color of this one is dark violet purple.
If you like the flowers and the roots are in good shape, its a good price. If the flowers are just kind of "meh" in your opinion or the roots are abysmal, then it is not worth picking up. I wouldn't worry about whether or not the plant is "rare". (And since it is tagless, I'm assuming you found it at a BBS or supermarket. The odds of those places getting anything truly rare is pretty mucn nonexistant.)
Thousands upon thousands of hybrids and then the variation within each crossing make it almost impossible to match hybrid photos.
There is a species Dendrobium that matches your description....google Den. victoria regina and view images...but as Paul says in the post above the odds are against you.
Was it similar to this?
This is Mingle's Sapphire a hybrid between Den. victoria-regina and Den. cerulea.