DON'T BUY A CHEAP 61 KEY KEYBOARD.
Let me repeat that for you.
DON'T BUY A CHEAP 61 KEY KEYBOARD.
If you spend a large portion of your time practicing on a cheap 61 key non-weighted keyboard, you will be completely worthless when it comes to showtime on an actual nice piano, not to mention you can get an actually decent piano for very little more. Spend just a little more money, and get a decent 88 key weighted keys piano. Get an old upright if you can, unless you plan on doing absolutely nothing but rock/pop stuff.
If you do want a keyboard for portability/space/etc try one of these out at a music store.
http://www.keyboardgalleria.com/Merchant5/merchant.mvc?Screen=PROD&Store_Code=KGMC&Product_Code=YAMAHA_P95&Category_Code=DIGITALPIANO
http://piano.about.com/od/keyboardreviews/gr/yamahaP85.htm
Very decent beginner pianos/keyboards with weighted keys, and other random sounds to screw around with.
One last thing. TAKE FARKING LESSONS. Yes, you can learn on your own. You can even get very good on your own. But you'll get good in literally half the time if you take lessons, as well as having a rock solid base(unlike me). I taught myself piano from about age 10(? off and on) to 20. I got to a decent level, for example, I could play Mozarts "Rondo Alla Turca" decently. But within six months of taking lessons with a very good concert pianist, and actually learning scales and such, I was playing through the first movement of Beethoven's Sonata Pathetique, and pretty well. I would suggest finding someone who goes to a local college, and find a high level(junior/senior) pianist, and taking lessons from them to start with. They will be at a pretty high level, but will also be cheaper than an actual professional. Also, be sure and tell them what you want to learn. If you want to just play by ear for the most part, then they will be able to help you with progressions/chords/scales/etc, which is different than if you just wanted to play classical/sheet music types only. I would try to do both, but really, tbh, I've found it pretty difficult to get good at both at the same time.
I taught myself piano for the most part, but decided to go a different route with the cello, I got lessons right off the bat. As a result, 1.5 years later, I'm about as good on the cello as I am the piano, despite only playing for about a 10th of the time. Maybe that will motivate you to get a teacher, lol.