Looking for less expensive protein shakes

I used to purchase the HMR shake product from Lowell General Hospital in Massachusetts. It was less expensive than some others. Some physicians carry a different product with lots more flavors but it is much more expensive. I once had a nutritionist friend whom I would pay up front, then she would purchase the product (only professionals can buy it) and have it shipped directly to me, without taking a cut of the price, so I got it at her price which made it affordable for me.  Anyway, I'm interested in knowing of sources for the products.
I'll be getting medical insurance in a few months and will then consider surgical options, though I am very wary of any approach that leaves something in my body.  I can lose weight, but haven't kept it off; more recently I have changed my diet and now for about 3 months I haven't gained, I've lost slightly. So I want to focus on diet (can't exercise because of bursitis L hip) and maybe consider fat removal surgery and loose skin surgery in a few months.
For now I'm interested in recommendations for as good a quality weight loss shake as I can get at a lower than market price, if I can.

How much were the shakes?  I LOVE Unjury  www.unjury.com   The containers are BIG and you get quite a lot of shakes and you can also order individual packs to try first...the vanilla (with a little bit of splenda) is my fav.    I have also heard there is a Walmart brand that meets requirements?  I have only heard of that but never tasted it..apparently people like it.

I use the muscle milk light.  I have tried many shakes, and this is the one I like the best.  I get it at Nashua Nutrition, and I buy it online.  You can get it at GNC also.  I pay about $25 and one container lasts me about a month.  I usually have one a day.  I like the chocolate with instant coffee or peanut butter, and the vanilla with crystal light orange or cherry pomegranate.  I didn't particularly like the strawberry. 

I should have been more clear. What I am looking for is a protein shake that is a complete food -- you can live on it.  I know that Medifast is, and one other one whose name I forget, that you can't order directly, you have to get it through a professional (MD, RN or nutritionist).    I am looking for a weight loss product.  I have never seen an off-the-shelf product in Walmart or anywhere else that is both a complete food (a complete meal replacement, you can live on it) and a weight loss product. Are you sure that GNC or Walmart carry such products?  I haven't looked recently, but in the past, the ones in those stores were clearly marked "not a weight loss product" or they indicated that they were supplements to, but not replacements for, regular food. 

Thanks

Have you tried Nashua Nutritition?  They are on-line and you could call them and ask if they have anything that would suit your needs.  I can't say enough good things about them.  They are wonderfully helpful and even if they don't have something that works for you they may be able to suggest somewhere that can help.  Good luck!
~Donna