What is the goal? Style, Color or function? Function is easy..I would remove the doors and the shelf? and buy baskets that fit. Drawers? If you have a solid bottom, buy trays with dividers and remove the drawer hardware? If color..paint is too easy to freshen up the vanity...try a gray or golden brown...whatever coordinates with a wall color...Style? Well it's a bath area. Do you want a taller unit..that may require a plumber too and new faucets? Some just paint...put down new countertop after removing the height of the drawers, purchase a crystal or copper or stainless bowl set atop the counter and reuse the faucet? That can be a pain because the sink is likely smaller and the water may splash and puddle, but it might be the right budget sized update if you are flipping, not living with it especially. You can spend less or more. If the unit is in good shape than the choices are more budget friendly initially...but if it does not function well, the expense is greater.