Since graphics card prices have come down, is it the right time to buy or wait for some more time?
And should I get a RTX 3060 12GB or a RTX 3060 ti 8GB ?
Depends on your budget & prices you can get for GPUs, it is still fluctuating. 3060Ti is in very high demand, has gone for as low as 45k but usually 50k. 3070 starts as low as 55k, but usually 60k.
3060 is 38k or so & 6650XT recently launched at 41k:
ASUS Dual Radeon RX 6650 XT OC Edition 8GB GDDR6 Graphic Card DUAL-RX6650XT-O8G
6650XT is slightly better (gap seems big based on this, but is very game dependent). Also, I feel 3060 is better for 1440p gaming because it closes gap with 6600XT & it has DLSS (can be used at quality mode if game is too much for it at 1440p render resolution, can use FSR as well with Nvidia whereas you only have FSR for AMD GPUs):