The best way to update the look of your kitchen is refacing or resurfacing your cabinets. Refacing your cabinets means replacing the doors, drawer fronts and hardware, and covering the sides and framework with a stick-on veneer or glued-on plywood.
Another way is by painting your cabinets. Painting is much cheaper than a refacing job, depending on finances, it may be your best choice. Some people also prefer the look of a painted cabinet to a natural wood surface. Like refacing, preparation for the job is crucial for a successful result.
Either way, the end result is a new-looking cabinet at half the cost. You also avoid the stress and inconvenience of completely removing and replacing your old cabinets. Not only is it cheaper, but it is faster, and less work. You can usually resurface your cabinets in a day, and get the satisfaction of having done it yourself.
Painting your cabinets is much cheaper than a do-it-yourself refacing project, so if money is an issue, it may be your best option. Some people also prefer the look and feel of a painted cabinet rather than a natural wood surface. Like refacing, preparation for the job is important for a fabulous result.
When it comes time to buy your paint and paint brush, cheapest is not the best here. Your result is that you get what you pay for. A brush is very important, and if it is cheap, it can cause brush marks and lines. I would even go as far as using a paint sprayer if you can. This can be time consuming with prep, but well worth it. The best final coat will come from a 2.5- or 3-inch brush. You'll need to apply at least two or three coats of paint depending on how the second coat looks.
Latex paints dry faster and are easier to clean up than oil-based paints, however, oil-based paints may give you a smoother surface. There are also paints specifically made for kitchen or bathrooms. Glossy or shiny finishes are easier to clean and typically have a tougher "shell" than matte finishes. The finish comes back to your own personal preference.
Both ways can give you a great new look to your kitchen cabinets, without the massive costs from replacing them.