If you don't mind long-distance travel, you can choose the train, which is the most economical. Generally, air-conditioned trains can reach Shaoguan Railway Station around 50 yuan. If it is a through train, it will cost about 100 yuan. But the advantage of taking the train is that you can see the beautiful scenery around you.
When you arrive at Shaoguan Railway Station, you'd better ask if the taxi can be full of companions to go to Danxia Mountain. If there is, it is best. Four people in one car, each 30 yuan, comfortable. It doesn't matter if you can't find it. There is a bus to Danxia Mountain at the bus stop next to the railway station. 12 yuan gets off at Renhua alone and walks for about 200 minutes to the Danxia ticket office.
It takes about 5-6 hours from Dongguan to Danxia.
The first time I went to Danxia was to find a hotel. I suggest you stay there for at least 2 days (watching sunsets, sunrises and climbing mountains). A hotel for 40 yuan a night is very good.
If you stay in 80 yuan for two nights, you can get a non-holiday ticket to 50 yuan (preferably with a certificate), and the round-trip fare is about 150 yuan. The food there is very cheap, and 50 yuan is rich in food, so it costs 330 yuan in total, but it needs to be reminded that there are many dry goods to buy and send to relatives as personal letters, so it is more than enough to take 500 yuan there.
All the above are personal opinions. I hope you have a nice trip!