Is it worth it to DIY kitchen cabinets?
If time doesn't matter, then go for it. It's fun and you'll take pride in your work. On paper, you'll save money, though I can almost guarantee that the cabinets will opportunity cost you more than just flat out buying them. Nobody can put an actual price on the materials without knowing more details... wood? melamine? doors and drawers outsourced or built by you? face frame or euro? nice hardware or basic stuff? 

However, if you want to be practical, find a supplier of RTA (ready to assemble) cabs. Cut out the evil orange middleman. I think you'll find them staggeringly cheap. (Some of them are actually quite horrible, quality-wise, so shop carefully.) Assemble them yourself. Install them yourself. Pat yourself on the back for a job well done. Apologize to anyone who had to share construction zone space with you. Double the apologies if the project runs longer than expected. (It will, btw.) 

I don't know where you are, but $6k sounds cheap to me.