G VS2 is already at the 'best bang for your bucks' regime - considering the fact that you dont mind G color.
Their pricing are already significantly cheaper than other stores hence it's kinda fixed and if you would like to have a better pricing, use UOB one card and split the payments over 2 quarter paying 2k every month to get 5% rebates, however do note that you will need to go down to the store every month for them to charge the card and you can only collect your ring after you've completed the payments.
Alternatively, check with them if you can get a small discount on cash payment (maybe just 1-2%), no guarantee on this tho, usually they will suggest you to use your credit card for rebates instead.
Thanks for the advice! Really helpful for me since it's likely to be my first and last time buying a diamond

G and VS2 was recommended to me too by the JP salesperson as the best value for money, on the basis that it will still be visually stunning when viewed in isolation, and the G colour wouldn't be visible unless one is a diamond expert or if viewed beside a higher colour grade diamond.
I was also considering the octagon cut, which is really nice when the diamond is viewed by itself (oriented with the tips pointing north and south), but which kinda lost it's uniqueness once it was set because the shape wasn't as prominent when viewed from a distance. The JP salesperson advised me to just choose a round brilliant super ideal with a larger carat weight which would be the same price as a smaller octagon


