Where does the cost savings come from, are you able to break it down for us?

SP is mandated to provide electricity at the given tarriff, which is updated every quarterly: https://www.ema.gov.sg/Residential_Electricity_...

However, OEM retailers are not. As such, they are able to give a discounted rate, in the form of discount off tarriff whcih ranges to about 20-25%, or a fixed discount rate which is currently about 28-30% discount. Interestingly, you pay less for a fixed rate, which is often not the case in real life-take for example mortage loans: the fixed rates are higher that that of a floating rate as you pay a premium for security. The gap between fixed rates and DOT rates are clsoing, and I predict that OEMs retailers will gradually raise their rates as the market matures. Finally, if you are not out to play the referral game nor interested in rebates, you can consider taking SP's wholesale plan by logging into SP services - click this tab 'Buy at Wholesale Electricity Prices'. AIM meter installation($42.80) is not compulsory as SP will charge you according to EMA's typical household load profile at the half-hourly wholesale rate. Calculations have shown the rates to be pretty competitive

Basically your "needs" and "wants". All depends on your lifestyle and the needs and wants can differ much based on individual.
To start off with, how much % of your monthly salary goes to expenses?
If it's more than 50%, then maybe can share your estimated income.