Specific to cruising budget, it can vary widely. In my three cruising lives, I have lived low, medium, and high budgets. The "low" started with a year in Baja California, where we spent $250 per month, never stayed in a marina, only ate out at taco stands, and didn''t carry boat or health insurance. We also bartered for a lot of stuff rather than spend cash.
I am now cruising on what I consider a "high" budget, which is around $1,500 per month NOT including boat insurance ($1,200 per year with no geographic/seasonal limits) and capital boat work like haul outs or major projects (we keep money in savings for that).
Thing is, budget depends a lot on where you are cruising, what you are cruising on, and what kind of lifestyle you want to lead.
There''s LOTS more to tell you! Feel free to contact me if you would like.