About a year ago I committed a petty theft in a store in my home country, the amount of things stolen was less than 10 USD. I was given a fine and never served jail time. Am I inadmissible to the US as a foreign Master's student or skilled worker?
Most questions regarding study and work abroad belong on Expatriates, but the statutory grounds of inadmissibility apply equally to those categories and to visitors.
A petty theft as described in the question does not trigger the statutory grounds of inadmissibility (8 USC 1182(a)(2)(A)), but it will present an obstacle that you will probably have trouble overcoming so soon after the conviction. This history could lead a visa officer or immigration officer to doubt your credibility or the good faith of your application. For an offence of this nature, the magnitude of this obstacle may be small, but a prudent visa applicant in your shoes should consider engaging an immigration lawyer, who should be able to help you address your history without appearing desperate.