Hello sir. As I have already answered your query in detail earlier. Your X-ray clearly shows a deep decay in the tooth no 7, a mild decay in 6 and also your wisdom molar shows decay (tooth no 8). As your dentist has already told u which is correct that u need root canal treatment in 7 and a filling in 6 after decay removal. The decay in 7 is very deep which has damaged the nerve of 7, hence it needs RCT. If u place a crown over the infected nerve, u will land up with a swelling or severe pain that will make your life miserable. So, better follow what your dentist is saying and do not try to overrule him/her and try heroic attempts. Any other dentist in the world will give you the same opinion even if u ask the same question repeatedly. The cost of a RCT depends on place to place, it can range between 2500 or above. The crown will cost depending on the type of crown u select, which will again be 2500 and above. So the treatment of 7 with crown will cost u atleast 5000 or more depending on the place and type of crown. The filling of tooth 6 should not cost more than 1500-2000.

Best is to do filling for 6 and for 7 you should opt for RCT and capping as the cavity looks quite deep and the pulp of the tooth may be affected. It needs to be correlated to your clinical symptoms