Hi you can try out Casio for entry range. Otherwise you can consider Priva or Yamaha but I tend to find Yamaha expensive unless there is promotion
You can check out these places for keyboards
City Music at Peace Center
Luthermusic.com
Swee Lee at Sim Ave
Sinamex at Peace Center basement
Best Denki for promotions (staff may not be as knowledgeable about the products though)
Go for those with 88 keys
If you don't mind there are many Carousell sellers selling their second hand keyboard. You can check it out too
You should test it out by playing it or at least ask the salesperson to play it. Don't depend on paper specification.