Got into a PhD program but no funding?
My advice for "typical" students seeking a Ph.D. degree is that you should not pay tuition for the degree and that you should receive assistantship or fellowship funding to compensate you for the time you spend working as a research/teaching trainee with a faculty advisor or advisors.

Reputable doctoral programs have access to one or both of the following types of assistantship funding: teaching assistantships funded by the department, college, or university; and/or research assistantships funded by individual faculty or sometimes by the department. Fellowship funding might come from the university or from external sources.

If a department or faculty advisor has not committed funding for your Ph.D., then this means that other students (new or continuing) have been selected for funding ahead of you. When they tell you that you might receive funding if things go well, it usually also means that either someone else must leave the program unexpectedly early or that they will commit some of next year's funding to you instead of to an applicant in next year's cycle. This sometimes does work out but puts all of the financial risk on you, the student. This is not fair. For this reason, my department does not allow unfunded Ph.D. students. Do not take an unfunded offer of Ph.D. admission.