10 nights at BC, lucky you! Yes, you can use them for your stay. The default is 14 days, but they extend it if you're staying longer. You just have to ask. The current pricing is 17.99 as of April, according to the refillable mug thread.
http://www.disboards.com/threads/refillable-mug-faq-new.3437666/
Please be aware that you will get them for "free" if you bought a package since it's included in the package price.