Yes, there are multiple flights from Bangkok Intl to Jinghong for under ฿ 50,994. The cheapest flight booked recently is on Multiple Airlines for just ฿ 48,474, but on average you can expect to pay ฿ 56,393.
There are no direct flights from Bangkok Intl to Jinghong, but Cheapflights can provide you with all the information you need to find the fastest route with the fewest stops.
When travelling, it's generally smart to pack in preparation for rain or any other conditions that may arise. The rainfall in Bangkok Intl is roughly similar to Jinghong. You can assume this to be the case over the next 3 days.
You can imagine temperatures to be in the 36 °C range in April. The weather in Jinghong is generally colder than Bangkok Intl's. As flight availability is subject to become more limited as peak season approaches it is ideal to book in a timely manner.