To be honest 25hrs seems rather little. Not only in terms of hours attached to the certification but also in terms of depth and quality of the instruction.
Having a limited budget doesn’t necessarily mean you have to cut down on quality.
Online courses can provide a thorough grounding in a new career and the right tools to approach a new profession within a manageable amount of time and finances. They are a good option particularly if you have a limited budget to further your studies or if you have other work and/or family commitments that restrict the amount of time you have available to study.
Many good schools around the world happily accept online TEFL Certificates issued by reputable organizations. So if you are looking for a way to get some basic training and a foot in the door, online training is an option worth considering.
Just make sure you choose a reliable course provider, and this applies to any course whether it is conducted online or onsite. For independent feedback on ICAL TEFL Certificate Course (100hrs) see here