"...they would include a credit line on each photo..." This is actually priceless James...
It places you an a category vastly above what others here are stating.
Especially those who are only selling prints (framed of otherwise)
I'm somewhat surprised at Gene's response...
At the zenith of this craft commercial photographers charge a "Day Rate" plus expenses and per diem as appropriate.
Shooting on prospect isn't a viable business plan... Nor is stock imagery
Named Credit is to be cherished... It separates you from "enthusiast" who pontificate about their "worth" yet have no Web Portal showcasing "Named Credit" tear sheets.
Take the $75 and Named Credit and do your very best to nurture this client James...
This is likely the wisest path for you moving forward in a quest to succeed as a commercial photographer.
Virtually all my work now comes from clients I've previously worked for and exceeded their expectations.
This is also true for my Bridal Makeup Artistry... "Referrals" are a key to commercial success!
FYI: I would suggest you look into the American Society of Media Photographers
https://www.asmp.org/Albeit you'll need a sponsor in order to join and a strong portfolio...
Here you'll be able to advertise your services on the ASMP web portal under "Assisting Photographers"
This was my path and served me well... Albeit the work can be brutally challenging (physically) though the pay can be extremely high. You will simply respond to queries with a "Day Rate" and per diem requirement.
(many of my "Assisting" gigs were up to a week in length plus an additional day to/from the site.
All the best on your journey James.
Please stay safe.