Hair extensions?

Ok I'm not even sure if that's what I'm looking for but my hair is so thin I was wondering if anybody got some hair clips to thicken up the do for the wedding day?
My hair is going to be all up anyway but don't want the bun to be this teeny tiny thing...
The only things I've seen are at those kiosk type things at the mall but those are like a ton of hair already attached to a huge clip.
I am so clueless about this, anybody have any suggestions (that aren't a ton of $$?!)
Thanks!

You can buy hair pieces that have wig clips on them, instead of buying the whole huge strand of hair.

You can find them at beauty salon supply stores.

I bought the long strand, and my Hair Stylist, attached the wig clips on her own, at no additional charge.

Thanks! How do they attach? Please no glue!! I hopefully want something that comes right out as we'll be leaving for HI the next day!!