I use KLB5 in place of MRC6 and purchase a 2 month supply for $24 at bariatricfoodsource.com (bariatricfoodsource.com/Bariatric_Vitamins_s/50.htm) - it's the same thing. Who knows if it works or not, eh? But I'm down 9 lbs and I am on Day 12!
I wouldn't purchase it for the $60 or so that they wanted at the center though - and I only purchased the low starter kit and the EFA pills from them - the 180 capsules/2 months supply for EFA is not a bad deal and they don't give you any fishy burps or aftertaste, so that is actually worth it to me.
I've been getting all my drinks from DietDirect (got $13 boxes for $94 w/free shipping last week) and all my other Vitamins (multi, calcium-magnesium, B6/B12) from my local Vitamin Shoppe. I don't think you should ever have to purchase another thing from your center once you sign up unless you want something special. I'd like to find a substitute for the Cortitrim that everyone raves about because no way I'm paying $75 for that, but haven't had any luck yet.