I have an Oxygen keyboard (M-Audio), which unfortunately must stay in Budapest.... If you lived there I'd tell my wife to ship it to you since it's not getting any use. Bought it from Guitar Center for about $100 and works great. Keys are weighted and the unit is entirely programmable. Can't remember the specific model number, I'll have to ask my wife that one later.
Depending on how serious you want to be about learning, become a two-handed player, etc, if you do go for the Oxygen model, I'd recommend the 61-key (4.5 octaves). It costs more though - US$250.
Shop for your Apple, Mac, iPhone and other computer products on Amazon.
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.