The petitioning employer files and pays the government charges set out in the USCIS fee schedule. Preparing the proprietary-product evidence and the payroll analysis is the larger internal cost, and repayment clauses should be settled in writing beforehand.
Evidence preparation dominates the bill
Hypothetical example: a Hampton integrator budgets a filing fee and a modest legal fee, then finds its development lead spending a fortnight assembling release documentation, licence agreements and training records, and its bookkeeper reconstructing a payroll history complicated by an early agency engagement. That internal time is the real cost of a marginal-year, proprietary-product petition.
What the government charges should be looked up at the moment of filing, since the published schedule is revised periodically, and buying a quicker decision is a separate election made on its own form. If the company intends to recover costs should the consultant resign early, that clause belongs in a signed agreement before the move, drafted with employment law advice on both sides of the border, rather than raised after an approval when the leverage has shifted.