When eyeing a used upright piano under $3000, some important factors can help you land a good deal.
If possible, its always best to have a local piano technician / tuner look at the piano first. They have the experience needed to guide your buying decision.
You can get started by checking the brand reputation. Yamaha, Kawai, and Baldwin are known for their durable and quality pianos, even in older models. Inspect the piano's condition closely. Look for scratches, dents, or any wear and tear on the outside. Inside, make sure the strings, soundboard, and action mechanism are in good shape.
Even if you don't play the piano (yet), test the sound quality by playing keys across the keyboard. Listen for consistent tone and watch out for buzzing or rattling sounds. Check the touch and action responsiveness. Keys should feel smooth and responsive, with consistent weight and rebound.
Ask if the piano has been played regularly, and when it was tuned last. A new set of strings for a piano can easily cost $1000 so you don't want to incur that cost at the outset. Also, budget 10% of the buying price for minor repairs and tuning. If a piano hasn't been tuned in many years, it might take the tuner 2 trips to get the piano in-tune.