I want to set up a portrait studio in my home. I'm a beginner to this type of photography, but have two kids and a not-so-patient dog to practice on as much as I'd like. I need advice on what type of equipment I should consider without breaking the bank (lighting, backdrops, etc.) This is strictly for me to take pictures of my own family so I'm not looking for an expensive professional set up. But...I'd also like to know if I should consider spending a little more now to keep from wanting/needing to upgrade later if I really get into this, which is entirely possible. Also, should I consider buying used, and if so, any advice on that? If it matters, I have a Nikon D80. Thanks so much everyone.

BTW, I also have a Nikon SB800 flash. Is this of any use to me for indoor studio portraits? I was thinking more along the lines of getting some kind of lights on stands with umbrellas and/or softboxes, but thought I'd ask about how my flash might be useful for taking portraits too.

I do not have any real advise as I am just starting to look at these things my self. However this website is THE place to start. Lots of great advise and equipment education.
strobist.blogspot.com lighting-101
DP

PS. Careful with old flashes. Some have been known to fry the electronics of digital cameras. If you buy used make sure you know the ones you buy are safe for digital.