It is an increasing trend that people are getting their phones without contract. For example, both Apple and Xiaomi sells their phone directly on their website.
Phones sold in Singapore are always unlocked because by law, it is illegal to sell locked phones in here.
As people change their phone more regularly, the two-year contract by telcos is no longer appealing.
Despite the phones being sold at a discounted price with your two-year contract, you are essentially paying more per month for your plan.
I am glad that Singtel has a new SIM Only Plan  that is contract free, data-centric and fully customisable.
Singtel is not the first to launch a SIM only plan. M1 was the first telco with their mySIM Plan .
The basic plan is a S$20 Starter Pack which includes 3GB local mobile data and 2GB Singtel Premium WiFi with free incoming calls and SMS.
S$20 for 3GB local data and 2GB Singtel Premium WiFi, free incoming calls and free incoming SMS
|Local Data (GB)||1GB||2GB||3GB||4GB||5GB||8GB||10GB||20GB||30GB|
|Local Data (GB)||S$5||S$10||S$15||S$20||S$25||S$40||S$50||S$100||S$150|
For example, if you take up the Starter Pack and decides to add 1GB of extra data, 200 mins of talktime but you do not need SMS, you will pay a total of S$20 + S$5 + S$5 = S$30/month.
My Use Case
Currently, for me I am paying S$42.90 for 200 mins of Talktime, 1,000 SMS and 2GB of Local Data. I topped up an extra 4GB of Local Data per month with DataMore Plan at S$34.24/month. I also paid extra S$5/month for Caller ID. So in total, I am paying S$42.90 + S$34.24 + S$5 = S$82.14/month.
If you convert my current usage excluding SMS (because I hardly use it) to the SIM only plan, I will be paying just $20 (Starter Pack) + 3GB Local Data ($15) + 200 mins Talktime ($5) + Caller ID ($5) = S$45/month. That is S$37.14 cheaper per month. If you multiplied it by 2 years, it will give me a savings of S$891.36.