IMHO, there are quite a few things to consider ...
Definitely factor in fills.
Depending on where you live, this can be an issue, as a lot of private doctors are no longer doing fills for 'out of country' banders.
The liability is too high, plus, they make no money off of us in the grand scheme of things.
For me, my fills have been $150CDN each, and I've had 5 fills.
If you get them done by a nurse who's experienced with gastric lapband adjustments, or a a fill centre (ie. Fill Centre USA - which I am not advocating, nor will the OCC based on the moderator comments in this forum), the cost is exuberant, you should source this prior to getting your band. I'm not sure there are a lot of options for fills right now. This is something a lot of people bother doing, and end up realizing it's a nightmare tracking down a doctor who will help them out. i've seen a number of doctors that just cringe, when I tell them where I got my band, and there's no way they'd touch it - the liability, unfamiliarity, etc.
Another thing to keep in mind; The band will probably require constant monitoring on fills or unfills. It's not a one shot deal.
MOST IMPORTANTLY --
Also factor in the price of HEALTHY FOOD (ie fresh food, protein supplements, ect)
On average, this will cost you, about $150, every 2 weeks.
And to ensure success, I would suggest a gym membership, so you can average in another $50/mth or so.
Depending on your emotional eating state, you'd probably need to factor in therapy as well at $100 visit.
Everything I've paid for out of pocket, and didn't put on credit or a loan.
This 'list' of costs is based on my own success.