Ditto
www.dietdirect.com - ProtiDiet concentrates are the ones I use - they go on sale for $8/box about every 2-3 months - the last time they ran that was at the beginning of June, so it's about time for it to roll around again. Ditto Deb - order enough to get the free shipping ($79 I think), and then wait for the sale to come around and stock up!
The only flavor that isn't very good is the Wild Berry - tastes nothing like MRC's - but the rest of them are pretty dead on. You can sign up for their weekly email, and that alerts you to what's on sale.
Also, been using EAS AdvantEdge in place of the MRC ready made chocolate shakes - just bought a 24 pack at Sam's Club for $27.99 - definitely the cheapest you can get those if you have want to do the Metaquick diet or use 2 for lunch as a meal replacement (1 as a creamy).