Negotiate a flat fee for the probate; or an hourly rate with a cap; or a payment scheme under which the lawyer gets some reasonable percentage of the estate; or find a lawyer with a lower hourly rate. That's really all you can do--don't hire a lawyer until you find one whose arrangements you are satisfied with. Or alternately: don't hire a lawyer at all: as an executor, you are legally allowe to proceed without an attorney in the vast majority of straightforward estates.