What is the differences between purchasing from Google and G Suite reseller. Is there any differences in the applications and services provided by both of them?

There are two ways to purchase G Suite which you may directly purchase it from Google or from Google reseller.
For the applications, all are the same no matter you choose to purchase with. However, if you choose to purchase G Suite from the reseller, you not only will get technical support from Google and also enjoy the various benefits that provided by the reseller.
If you purchase from Google official website, it will show Singapore dollar in term of the sales pricing and the reseller that provide services will be different accordingly. However, all of the resellers had also sacrificed their own margin in order to provide better pricing for the customers especially when there is a transfer and renew customer which does not have more flexible pricing. Therefore, the reseller will offer more attractive pricing for the customer in order to attract more new customers.