They are kefir grains.

Hi,
It called - Kefir Grains or Milk Mushroom or Tibetan Mushroom - all the same.

It, indeed, is Priceless - as far as Health Benefits but nowadays it does not cost a Fortune (it used too!) - now, you can get it very reasonably ($10-$15 plus S&H)on Internet from several sites - including ebay. Make sure you getting the Grains - not a Starter culture! Just do the search by google!
But, you do not need to do it - just wait until it grows enough and your friend could share it with you later...

Grains will double in size every 2-3 weeks - if your friend ferment it in Real Milk. (it will not grow in substitute milk)

Ask your Friend, if he has a good strainer - to catch all tiny "babies": the Grains are constantly separate - but if the holes are big - he will "lose" a lot of them...
To be exact - he actually will drink them up with kefir, which is good for him - since they (the grains and Kefiran in them) have medicinal properties. Yes, you can consume the Grains - when you grow enough of them - they cure many problems.

I, personally, made small bag from Cheese Cloth (double layer) and ferment my Grains in it - since, I do not want to "lose" any small babies - i have friends on waiting list for those grains...
And, also, I want to have enough of them for myself to make not just Kefir - but my own live cheeses - like bri or blue cheese! And for many, many other uses!