You don't need a lot of initial capital to get your own business today and be very successful. In fact, there are more chances of getting successful in the online world than you can ever have in the offline world. This is because everything is done through a simple Internet connection and a well-designed website.
SEM is basically how websites communicate with search engines to identify what it's all about and which searchers they match perfectly. You may get navigated to https://www.designmemarketing.com/seo-company/ if you want to hire professionals for SEM.
Life without SEM
If you are not worried about SEM and only managing your online business, you will not get the traffic to your site that you need to be successful.
Millions of people search with search engines every day, but they won't find you because you communicate with search engines to get ranked and be presented on the results page.
You must rely on word of mouth advertising and handing out your business cards to attract people to your website. This might work to some extent if you are a big business with established customers or who others might be looking for online.
But even the largest business in the offline world now uses online search engine marketing, so even having a big name is not enough today.