For a new piano, I recommend shopping around and playing on the pianos that appeal to you. Each piano will feel different. You might like the feel of one, and not the other. Buying a piano is a huge decision, so be selective.
I would avoid finding a used one (from an individual) unless you have a professional piano tuner look at it before you purchase.

For a keyboard, I recommend at least 61 keys with touch sensitivity. My preferred brand is Yamaha. Keyboards are easy and inexpensive to purchase and are more than sufficient to learn piano on.