This video from LIL PIZZA rounds up a bunch of so-called unlimited money glitches in GTA Online. Based on the title and preview, it looks like a test of several different methods, likely involving the usual suspects like replay glitches, solo session tricks, or mission exploits. The cover suggests a montage of attempts, some of which probably work and others that fail spectacularly.
Keep in mind that any glitch featured here is likely already patched or will be within days. Rockstar is aggressive about fixing these, so do not assume it works just because the video is up. Also, using glitches to make money carries a real ban risk, especially if you do it repeatedly or rack up a huge balance. It is not a legitimate method, so treat it as a gamble.
Before you spend time setting anything up, check the video's upload date and read recent comments to see if people confirm it still works. If the comments are full of "patched" reports, skip it and look for current, verified methods instead.
