You should never pay to shop and it is certainly not necessary to pay a referral service to send you leads on jobs. The way that this works is you sign up with companies, you request jobs from them or self assign jobs, you study the instructions, you perform the visit, you report the shop, you upload any receipts or other materials required, you watch your E mail for any questions or clarifications the editor needs for your report, and then you wait for payment. Legitimate companies do not ask you to pay to shop for them.