The decision whether root canal treatment is required or not depends on the clinician after radiographic evaluation. If he/ she suggested you for rct, it much be after proper evaluation and regarding the cost factor... it varies from one clinician to another based on the quality of treatment they provide.
Next Steps
To just relieve the pain..some painkillers might help you ..but it's temporary and not for the actual cause. Better get your treatment done at the earliest before the damage is done beyond repair.
Health Tips
If you are visiting Kolkata anytime soon..can contact me for the procedure.