need help to find cheap protien fruit drink ( Powder)

I need to see if any one knows of a fruit flavered cheap powder protien drink....MY cousion had surgery around two months ago and He can not tolarate milk or lactoid free milk or soy  ect...He has gotton two ulcers sence the surgery too. He is mentely challaged and having a rough time...He gets sick and has ended in the hosp several times...I told him I would try to find him something fruity..He loves the banna flavor but the milk Is really bothring him.. He needs  cheap ,cheap ....Any suggestions would be great...He is a sweety and trying so hard...He is so glad for this surgery and just hates to get sick...  thanks sandra