Strangers keep sending a string of messages with $. What happened?

It may be fraud or harassing information.

If there is only one number, and the number is a normal mobile phone number, it is recommended to call and ask. If it is a remote number and most of them are virtual numbers, it is recommended to turn on the mobile phone interception mode, which can intercept most of them. Do not click on those that cannot be intercepted, which may be fraudulent information, harassing advertisements or Trojan virus.

With Trojan information, it will be downloaded and installed automatically as long as you click it, and installed on your mobile phone without your consent, even if you want to install it. Poisoning will cause information leakage, and even automatically record and forward your bank card password and card number, thus stealing money from your card.