Welcome to the forum! While mystery shopping can help with financial situations, it is hardly a panacea for all of them. It takes time and patience to get registered with enough companies to regularly find jobs and it takes time and patience for the cash flow from shops performed to begin trickling in. The key factors for meeting your goal include where you live (urban is more productive than rural for finding jobs), how flexible your schedule is to perform shops with specific time/date windows, and how well you follow directions to submit usable work.
Best wishes as you undertake this endeavor. To help you get started you will find at the bottom of each page of this forum a link to our list of legitimate mystery shopping companies. Avail yourself of the New Mystery Shopper area of the forum as it will provide you with many tools and much information for getting your business set up. And this is a business, so keep good records because as an independent contractor nobody else is going to keep them for you.