How much income do I need to be making a year in order to sponsor my mom if I’m single with no kids?

Information about income requirements for a U.S. adult child to sponsor a parent may be found here: https://www.uscis.gov/i-864p. If you have insufficient documentable income, then it may be necessary to have a joint sponsor. Generally any U.S. citizen or Permanent Resident who has sufficient documentable income and who is willing to assume the responsibilities contemplated in the Affidavit of Support document may qualify as a joint sponsor. Of course, there are many additional details that impact eligibility; it would be wise for you and your mother to consult with an immigration attorney who, after learning all of the relevant information, could advise about eligibilities, options and strategies to attain your goals, and who then could offer legal representation in the often complex application process.