Hi, sorry I haven't been on the forum lately. I hope you are well!
Strata & Mepitel and certainly the more superior skin care products, both expensive. If she has to buy strata herself (some hospitals will give out a discount code so might be worth asking) she can use it sparingly (a little goes a long way, I'm talking about a little finger nail worth over the whole breast) and put another product (Moo Goo is great) over the top but ensure the strata has fully dried first (as it forms a protective film- much like the Mepitel). Technically you shouldn't need to use anything else but I find it hard to tell where its been applied so another over the top would pick up any missed spots.
I hope that helps? Best wishes to your friend x