The problem with getting a keyboard for the first time is that we tend to make a cheap choice thinking it will be acceptable. If you do this you will quickly want to change to a better model which with part ex-change is going to cost you more than buying a better keyboard in the first place.
If cost is limited keyboard wise the Korg PA50 is their low priced keyboard and is excellent value at £699 UK. Costing much more but the best value in the Yamaha range is PSR3000.
If it's Piano style you decide on look at the Yamaha DGX models.
All these can be obtained used models at reduced prices.