THC-O is more expensive than other compounds such as Delta-8 because it is more difficult to produce. However, since THC-O is much more potent than Delta-8, you'll likely need to use less THC-O for each use, so the price could be matched. To get a THC-O vape cartridge that contains potent THC-O oil, you must find a transparent company, reports from independent laboratories, and be accountable to your customers. The multi-step process for creating THC-O begins with hemp-derived CBD and includes acids and filtration to convert the compound into THC-O acetate.
This is also why it's important to buy only THC-O products from a reputable and reliable source that uses an experienced manufacturer and a cGMP compliant manufacturing plant.