Teach me what? To not make dumb mistakes? Selling it isn't worth it, the $5 dollar difference isn't enough to justify selling a used chip or paying for shipping
I changed a few of the pricing points ($1200, $2400) because there are fewer and fewer go-betweens for price the more powerful the hardware gets. I didn't include OS or cases because they come down to personal preference most of the time. I budgeted space for the case but not the OS. Rebates are included. I didn't include internal disk drives/burners because they're almost 100% useless unless you know for a fact you have a recurring purpose for them. If you want one just take it out of the case budget. REMEMBER, these are suggestions, so if you disagree with a choice I've made, make sure it is a valid reason and not just because you have a personal vendetta against SSDs or whatever else