Finding all the right data on dune and familiarizing oneself with the set of contracts that your project is working with is a lot of work and dune freelancers aren't called "wizards" for no reason.
Good dashboards range from 1000-6000$, depending on the scope of your project and how many different products, contracts and complexity is involved.
Paying well certainly brings more (freelancer's) eyes to your project and gets more skilled freelancers interested.
Be prepared that you will probably need to incentivize maintenance of the dashboards as well, so a "set and forget" solution is hard to construe(it's possible in some cases though if you don't launch new products).
Maintenance is way less work though and should be not as costly.
What we would like to see is wizards getting picked up more permanently as a part of the respective teams, but that's all up to you and the freelancer to hash out specifics, you can hire them for one time work as well.
If you are doubting how much you should pay, you can always reach out to our community manager 0xboxer(0xBoxer#7679,
t.me/0xboxer) to get a feel for how complicated the task may be.