I bought an ikea kitchen and in the end it ended up costing us the same as if we used a contractor. Ikea is great, but Traemand (the installation company) is the absolute worst. I paid them 200 to come out and measure my kitchen. I wanted the exact same layout. Literally nothing was changing except new cabinets and what do you know. The guy came over measured without touching the cabinets and ultimately ordered the wrong thing. Anna from Traemand told "well you signed the paper". I explained to her that I was looking at a picture of my new kitchen (a bunch of squares on a paper) and I asked multiple times to explain what I was looking at and had them confirm it was exactly what I ordered. Traemand rescheduled my install 2 days before they were supposed to start and once again Anna said "well you agreed to let us reschedule" to which I asked if I had a choice. I didn't not. So ikea contracts their work out to a company who is the absolute worst and will cost you way more than you planned. So for big projects just pay for the contractor and get your parts from Home Depot.
Oh and chivino surfaces also cut the whole for my sink too small adding to the dollar amount. So save yourself the headache. Small items and diy things from here are awesome.