There are various dimensions in a job to be motivated by, not just what you get paid. Your training period, kind of work, kind of team, and the other things you value, like work-life balance, for instance.
You also need to understand what the company values. Salary is a recurring cost, that increases over time while being a subject of gossip due to inequality. A joining bonus is a one-time expense and isn't public.
There are other perks to negotiate for, like relocation bonus, which can be easier to arrange.