With the .biz extension, I don't see it being worth all that much. Most gift shops simply use their name as their url, I can't see many people remembering this url with the .biz.
see how different extension affects prices (estibot valuations, I woult tend to agree with most of them in this case) giftshop.com $223K USD giftshop.net $7K USD giftshop.org $3.8K USD giftshop.co $2.9K USD giftshop.us $1.9K USD giftshop.biz $40 USD - here I would adjust it, as it has value 200-1000 USD imo for right end user.