People remodel and throw out old cabinets or retire them to the garage all the time. The problem is that it is going to be difficult to get enough matching cabinets from someones dischards, to fit your custom kitchen plan.
Have you thought of building your own? If you can join wood, you can get a lot of quality cabinets with hardwood faceframes and plywood sides and shelves for very little money.
Another possibility is to get the really inexpensive Mills Pride assemble yourself cabinetes from Home Depot. They come in standard sizes so they can be replaced later if desired. Best of all, they look pretty good. You can create a customized kitchen from these. If necessary, buy base cabinets now and have a serviceable kitchen and get wall cabinets when money allows. The styles don't change often. Shop your options.