Friend needs to send packages from UK to Germany what is the cheapest way?

Question

She has about 15kg in 3 boxes?

Answer 1

I am not sure about the UK, but here I would use the post office.  It is the simplest way, and usually very economical.

Answer 2

The cheapest way is to make the packages up to 2kg.  As soon as it goes over the kg mark the price rockets - like seriously.  

So make it in to 8 packages and mail it royal mail. :)