RIR cost info

HR or your boss will review all the application and decide phone interview to reject or accept the possible applicants. Usually your advertisement already has detail information for applicants. although you could receive hundreds of resume, maybe one or two or three need to be phone-interviewed. your boss or HR always can find a way to turn them down if they really want to help you for GC application.
lawyer fee is different for different state. I am in Dallas, they charge me $1000 before they prepared the Ads, then another $1000 after they filed LC ETA-750AB. They will take $1800 when LC approves and file 140 and 485. since my LC is still pending, I haven't pay that money. all those fees don't include Advertisement fees for LC, filing fees for 140 485.
good luck for you.