In the simplest case, only two people participate in tenders: a tender specialist and an appraiser.
The tender specialist is grown either from a person who has worked with tenders before or from a clerk. An appraiser is the head of a company or a top manager: serious decisions are made here.
90% of the work (in time) is done by a tender specialist. After the first 10-20 tenders he stops making mistakes in the documents and draws up and submits everything himself.
The remaining 10% is the work of the top manager/director, who evaluates the work on the totality of "cost - terms - conditions", plus some other factors (familiar customer, security and current financial cushion, etc.).
Front-end: $25
Back-end: $25 (PHP), $35 (JAVA, C#), $35 (Ruby, Python)
Analytics: $35 — $45
Mobile: $30
Design: $25 (designer), $35 (Art Director)
DevOps: $30
Testing: $20