I think I paid around £3 for postage as and when they came out. I lost interest in the magazine though about 6 months ago so no idea how much postage has inflated. I did buy my first issue straight from Germany but it actually cost me more than buying from amigakit. also took longer.
edit: thinking about it, if it cost me more to have it shipped from germany, then it makes sense that amigakit charge almost £4 as even buying in bulk they've gotta cover the cost of shipping from Germany to them, then from them to you. They sell the magazines for the same price as germany so i doubt they actually make much if anything at all