Is it permissible to benefit from websites that offer paid courses for free, but without a certificate or follow-up, instead of paying for them?

If the courses are available with the permission of the copyright holder, then there is no problem in benefiting from them. However, if they are available without permission, it is not permissible to benefit from them, because intellectual property rights are protected and owned by their holders, and it is not permissible to infringe upon them.