I think (just my opinion) a thank you card and a small gift are nice.
By small, I mean no more than maybe $25. I started to say $10 but remembered that milk, bread, eggs, just basic stuff costs that much.
Take in some bagels and cream cheese or holiday cookies for the whole group that helped you and a gift card
to someplace your preceptor likes is nice.
If money is a problem for you, don't do the group thing now but do it after you've been working there for a while.
What types of gifts are you considering? And how many preceptors are you talking about?