The monthly fee is $49.95 to be a VIP member but you have until the 10th of each month to skip and not be charged anything. Basically, it's just like JustFab, in that you never have to make a purchase if you don't want to. You do however, have to remember to skip each month! Becoming a VIP member offers significant savings on outfits (up to 40%), but you can purchase items separately as well.
After browsing the site, the clothing doesn't seem to be anything too special or different design wise. Hopefully that will change as time goes on. There are a variety of basics offered from sports bras, tanks, capris, leggings, etc. I'm not a huge fitness buff by any means but I'm sure the lululemon addicts out there will agree, you pay for the quality of the fabric.
Being that Fabletics is still very new, there aren't many reviews out yet. However, from the ones I have read, Fabletics seems to be providing some quality stuff!
I just ordered an outfit and I'm excited to see for myself. I picked out the 'Reveal' outfit which included 3 items for $49.95:
Omemee Sports Bra
*Pictures taken from Fabletics.com, referral links provided*