I often get asked, ‘How can I budget if my income varies month to month?' Simple, average your monthly salary and keep those expenses as fixed as possible.
When I first started in Real Estate, the closings were scarce. To help, I kept my expenses to the basics + drinks/clubbin' (single, no kids, 20s; you know how that is 🙂 ) and made use of those larger commissions by saving as much of it as possible to cover future expenses for the upcoming months.
Key point: Yes, your income varies, but when those good months hit, do not spend it. Stretch it to cover the months when your income is $0 to very little.
Hope this helps!