Get single stick with high capacity. No need to use dual channel like in DDR4.
Prefer highest speed, 5600Mhz so that you get good resale value later. If your CPU/motherboard only supports lower speed like 4800Mhz the 5600Mhz RAM will run at a lower speed anyways. And since you have limited slots, prefer higher capacity RAM.
Crucial 8GB DDR5 → 5600Mhz | 4800Mhz
Crucial 16GB DDR5 → 5600Mhz | 4800Mhz
Crucial 32GB DDR5 → 5600Mhz | 4800Mhz
Rs. 2500 Crucial 16GB DDR4 3200Mhz → Amazon India: CT16G4SFRA32A
Rs. 1300 Crucial 8GB DDR4 3200Mhz → Amazon India: CT8G4SFRA32A | Variant 2
Only if you don't find the seller for Crucial from above.
Rs.2400 G.SKILL Ripjaws 16GB DDR4 3200Mhz → Amazon India: F4-3200C22S-16GRS
Rs.1100 G.SKILL Ripjaws 8GB DDR4 3200Mhz → Amazon India: F4-3200C22S-8GRS