How is that obvious?
What did the dentist tell you, that you needed a root canal, or a root canal and crown? Is the tooth broken and or rotted?
Anyone you email has not seen the tooth, so they have no idea what is needed.
I use Bangkok Hospital Dental Center in Bangkok and they are great.
It should cost about B1,200-3,000 with an x-rays to have them evaluate it, tell you what you need and provide a quote.