Ah. I was thinking you wanted to make a desk, not just the top, which you could do with the 4x8 sheet, some screws, and maybe a two by four. (Am I imagining things? or did you edit your original post to say bookshelf rather than desk? it's okay, I edit my posts too; you could also make a bookshelf out of that 4x8 sheet, if your time was free and you had the carpentry skills.)
Even so, the 3' x 2' bit of 'wood product' from ikea costs almost as much as a 4'x8' piece of 'wood product' from home depot. That's more than 5 ikea tables worth of wood.
I think the dramatically increased price (percentage wise, of course, not dollar wise) of the ikea part is in the addition of the laminate on top and on the sides; you can't really cut the laminated particle board to size once you get it, unless you want exposed sawdust-wood, so we are back to manu
I mean, I'm not saying the ikea stuff isn't good; I'm just saying that they, generally speaking, are charging considerably more (as a percentage, not in terms of dollars, and for a $7 item, even if their markup is 4x, well, you probably aren't going to notice.) than what materials cost.
