No they don't sell the MAC Chain, it is only for MAC Makeup Artists/Employees... Sometimes you will see them being sold on Ebay, but that is technically illegal since MAC Employees are forbidden to sell their necklaces/memorabilia.
I could have bought one before working for MAC, but it wouldn't have meant anything since I didn't "earn" it, you know? I don't like how people will sell them...
Oh and I don't use a primer... I wash my face, then moisturize with Strobe Cream and then put on my foundation, concealer and loose powder to set.