According to your conversation I think your left side tooth is grossly destructed n we can't save this tooth thatswhy your dentist
told to get extration f this tooth.
N in right side I think deep caries which can save the tooth by doing root canal treatment
(r. C. T) n placing cap over this.
It means your treatment
1 extraction (left side tooth)-500-800/
2. Rct +capping (right side)- 1200to 2000+1200to 1800
n charge varies according to area, n dentist to dentist. I am giving you just gross estimate.