LuLu says- If you wanted your book to be available through other online stores - to go into 'distribution', in other words - all of those costs are doubled. You can reduce this by reducing your royalty, which is what most people wind up doing, which also reduces Lulu's commission and therefore the whole cost of the book.
The extra double costs goes to the retailers as their profit margin. Usually they reduce this so that your book may not actually sell at that full price - the retailers can offer 'special offers' etc simply by reducing their profit margin. You'll find some dealers in the Amazon marketplace do this quite quickly (while others seem to add outrageous amounts to the price of your book - they won't sell any, but hey, that's capitalism for you.) Your book on the online retailers will start to show a reduction in price that makes it more competitive, but you will always get your royalty, whatever price the book is sold at.
The cost may seem expensive, but don't forget that traditional publishers print books in hundreds and often thousands, which means the cost of manufacturing is reduced per book. Print on Demand is earth friendly which means higher costs.