Depending on what paperwork you need, if stuff needs to be legalized, it can add up a bit. But nothing near paying an agent for anything. Just be prepared for a couple of trips to immigration since it is never okay the first time.
What breaks the bank is subjective. I would never pay, grow a spine. This is literally just shaking some money out of someones pocket for something millions have for free.
Applying is such a pain though...I am also redoing it because the time to renew was so inconvenient. Maybe pay for an agent once? For the funds that is.