Don't Ask Brands for Their Budget; Ask for a Budget Range
At the end of your discovery call, if the brand somehow backs you into a corner and says, "So, how much do you typically charge for this kind of thing?" you must avoid coughing up a number you'll later cry/curse about in the shower.
Instead say,
"Thank you again for this call, as it's been super useful. I need time to think through everything, and then I'd love to get back to you with a custom proposal. Typically, I like to put together 3-4 packages to help you envision how we can bring this partnership to life. Do you have a sense of what I should set those 3-4 tiers at from a budget feasibility perspective?"
And then…shut up.
Don't say anything.
Lean into the silence.
I (as well as hundreds of my students) have used this exact method countless times, and one of two things will happen:
75% of the time the brand will tell you their budget range!
They'll say something like, "$1K, $2K, $3K" or, "$15K, $30K, $45K."
The brand feels more comfortable sharing because they now have wiggle room to modify the amount they'll ultimately pay you, if necessary.

You'll also learn:
Roughly where to set the minimum investment for Package 1
Roughly where to set the investment for the top Package (it should be above the highest range they gave you!)
How much time you should spend on the proposal (If I hear $10,000 vs. $100, I'm definitely putting in some extra hours)
But what about the 25% of the time when brands won't tell you their budget range?
My unscientific advice in these scenarios is to set the investment for Package 1 at your "Hell Yeah" number.
If the brand chooses Package 1, you should say, "Hell Yeah, let's do this!"
Not, "Aww bummer, I was hoping they'd pick Package 4. Now I have to do this."
The last thing you want is to start resenting the brand at the very outset of the collaboration.

Get the ongoing support you need to set win-win pricing, submit spellbinding proposals, and negotiate like a pro.