Government charges are the Form I-129 fee with the L supplement, set out in the USCIS fee schedule at Form G-1055, and premium processing if the affiliate needs certainty on dates. The dominant cost is assembling and, where necessary, creating the evidentiary record that proves the knowledge is proprietary.
Most of the bill is document work
Small manufacturers rarely keep their technical knowledge in a form a stranger can audit. Making the file usually means retrieving drawings from a former engineer's drive, reconstructing when the anchoring specification was written and by whom, formalizing a training curriculum that has always been delivered verbally, and writing down a load-testing procedure that lives in one person's practice. That effort has value beyond the petition, since it is the same work a company does before it can scale or sell, but it is billed hours and internal time all the same.
Add legal drafting, the response to any request for evidence, and translations where documents are not in English. Fee amounts published by USCIS are revised periodically, so check the schedule at filing rather than budgeting from a prior case. Weigh all of it against the cost of losing a season in the American market because the specialist could not be placed.