Is it worth to stay in a "small" company whos bosses (husband and wife-owners) who shouts at you when you make mistake? And..?

is the money worth having something to eat every day

Did you tell him that you didn't understand the xx and you won't mess that up again? You can then tell him that he doesn't have to yell to get through to you. However, if you are continually messing up, perhaps that job is not for you. Go and find another job. I cannot imagine how demeaning it must feel.

If you can find another job elsewhere with comparable pay, take it...

No. These establishments are very 'family like' and I despise them. I once tried to work for one as a receptionist. I had always been told I had a polite phone manner, if a bit casual. On day one, the 'mom' of the business overheard me on the phone and informed me that I was not to use the word 'okay,' as that was not professional. I have used that word every day of my life, and knew she was just being stupid. I packed my stuff and left the place, pronto. Life is too short to have to put up with mowrons.

I would keep this position until you are able to find another job. Jobs are too hard to find to quit one before you have secured another position. Once you have found a job that you like, give 2 weeks notice to them, as an act of good faith, so you don't burn bridges, and then go onto your new position.

and what?

We don't know if such a job is 'worth it' to you or not. We don't know what you're paid, what benefits you get, if you like your schedule, if you aren't bothered by the yelling, etc.

Generally, small office jobs have few benefits and possibly no type of pension plan for the future, so unless you have a spouse with a job that has good benefits and will help you two get set up for retirement, it would probably behoove you to find a job where you are happy and you are receiving the compensation (salary and any benefits) that you feel is appropriate for you and your future.

What is not smart is to quit a job before you have secured another one in its place. What is not smart is to think your boss, no matter where you work won't be angry when you make a mistake