As such there is neither any toothpaste to reduce tooth pain, nor any minimum charge for root canal treatment.
Having said that, even if some sensitivity toothpaste/ clove oil/etc reduces your tooth pain temporarily, don't delay visiting a dental surgeon as that will further damage your teeth or gums, to a point that it may never be restored. Visit a dental surgeon at the earliest for a proper diagnosis and advice regarding the treatment as medicines only temporarily provide relief but doesn't treat the dental problem.
Next, regarding the charge, you will find varying rates as other specialists have said, but definitely go for quality work rather than seeing the money as obviously the charge depends on the skill of the dental surgeon and the materials he/ she is using for restoration of the tooth.
Next Steps
Visit a dental surgeon at the earliest.