My husband and I need to buy a new dishwasher, but cannot afford to redo our whole kitchen right now. We currently have outdated black and white stove and refrigerator and a black microwave. We like the stainless look better. Should we go ahead and buy the stainless dishwasher in hopes of being able to replace the other appliances later, or do we keep the same look so everything looks put together if we were to sell?

I think if it were me, I would look for a dishwasher with changeable front panels. Kenmore should still make them, I think, and they used to be actually manufactured by Whirlpool, but I have no idea if that is still true. The front panels and kick plates are quite easy to change when you update the rest of your kitchen.

This is a hard answer. You do not want to put into the kitchen to many appliances that do not match.
Many dishwashers today have removable fronts. The trim edges on them come off to allow for the panel to be slid out and changed.

The stainless units oftentimes do not have this ability. I would if it was me keep the same look.

Many folks as well I love the look of the stainless kitchen. But the cost as you already know is quite high. If you get to the point where you can change to the stainless look adding the diswasher to the mix should not break the bank. I would wait until you have the cash on hand and do them all at once.

Another point to ponder. Stainless appliances overpower a kitchen that is small very fast. The idea of stainless is to mimic the look of the commercial kitchens with some flare. But true stainless kitchen appliances tend to be larger looking and more bulky. Thus the overpowering look.
Also stainless appliances tend to show every fingerprint and spot.