I would really prefer a face to face deal in ncr (really pref delhi or gurgaon) .
My ranges for these cards (depending on warranty, brand and your trust score ie Ill pay higher if you are a reliable seller)-
rx 6600 - 15-18k
rx 6500 xt - 8-9k
rx 6400 - 7k (this is like a last resort for me...
If he can spend a little more for an apu build apu can outperform in newer titles and gives a better upgrade path. 750ti and rx560 suffer from vram bottlenecking. It is better to recommend a second hand t400 4gb. Those used to sell for a decent price.
The 4650g outperforms the 3400g in basically all games. Heck it even beats the 1030 and 750ti in newer games due to older games being vram bottlnecked.
Honestly the A320M you listed here is the cheapest AM4 board available in the market. If you go to a physical store and bargain a little you could probably get one for 3300 or 3200. Check olx and quickr too I had seen some combo listings in NCR.
Dont buy low end cards like 1030 anymore please. Unless you have a cpu without a igpu the current Vega apus literally beat 1030 in modern titles. Instead go for atleast a second 1050ti or equivalant.