I worried a ton about this early on and finally made my mind up to be completely honest about it to everyone.
My fear was that people would think I was somehow taking an easy way out or that I was just being lazy. In reality, I have had nothing but support from my friends and family and now that I'm losing weight they are even a bit jealous or ask me tons of questions as if they might want to do it themselves.
Truth is, your real friends will support you regardless. I tell them that the band is simply a backstop for me when I struggle to do it on my own -- it's not a guranteed fix, but provides me the support I need when my brain isn't cooperating with my desire to binge.
When the question of cost comes up, I simply ask them to ask any person that is over 100lbs overweight if they would trade their car to be healthy and thin. 99% would in a heartbeat.
Hope that helps.