Which mobile card is best for texting between couples?

Mobile services in Changchun, Hainan, Zhejiang are very cheap, about 30 to 40, and there are more than 1,000 lines! But I recommend a better card is China Unicom in Guangzhou, it is very affordable, the card is free, you can buy two The card (a card is like 60 yuan and comes with 60 phone calls). The monthly fee is 10 yuan and you can get 100 text messages regardless of the network. The key is that you set each other as a family number. Each person only spends 3 yuan to send unlimited messages! ! Really, it turns out that I only use this card, and even if I send 100,000 messages, it only costs 13 yuan a month! Turn off the caller ID before using it!