Checking how it is delivered before you commit

The word "online" covers two very different products. One is live teaching at fixed times with a real cohort around you. The other is recorded material you work through alone with an assessment at the end. Both are legitimate. They are not the same purchase, and the price frequently does not tell you which one you are buying.

Ask directly: how many hours are live, is there a cohort, who marks the work and how quickly, what contact do I get with an academic, and what happens if I fall behind. Ask for a sample module. A provider who cannot answer those plainly has told you something.