It is a source of confusion for many foreigners when they realize that there is actually a minimum wage that they must be paid to be sponsored on an H-1B Visa, E-3 Visa or O-1 Visa that is not related to general US minimum wage law. This is known as the Prevailing Wage and it differs by progression, level, geography and nature of the role.
When an employer files the ETA-9035(e) form to the Department of Labor (DOL) to get your approved Labor Condition Application (LCA), a part of that form relates to inputting the Prevailing Wage from a verified source. This is the only step required in a standard E-3 visa application prior to an applicant going to their US Consulate interview if outside the country but it is the preceding step to filing the I-129 form to the USCIS which is mandatory for H-1B visa, the O-1 Visa and for the E-3 Visa if the applicant is already present in the US under an approved status.
The actual Prevailing Wage can be slightly subjective but the important thing to note is that it is never a very low amount and the LCA can be rejected if the DOL determines it is not the appropriate job code and pay level given your role. Many foreigners fall at this step in their eagerness to get to the US they are willing to be paid a lot less for the chance not realizing this is part of the process.
The are a few government approved sources but the most common is the FLC Data Center. They have a wizard where you can enter your location and job type and you can manually find which job code is most suitable relative to the role you are going to fill and the Level from I to IV which largely corresponds to seniority.
It is here with job codes and similar job types and the seniority that people get creative with what job code is suitable to match their pay level. However you want to be careful as if you are a professional leading a team and you just put down a Level I, Entry Level Job code for your job type, you could be rejected and face additional scrutiny for any future application. As mentioned these job rates relate to professional jobs so the rates are far higher than any minimum wage level for the state.
Also it is worthwhile noting there will be significant differences for the same role depending on your location. A Business Analyst working for Ernst & Young for example in NYC will have to be paid more than if they were working in Seattle at the minimum allowed level. Ultimately you should negotiate the best wage, benefits, bonus, equity and severance package policy at the beginning and this minimum level should never be an issue