Hi,
I will try to keep this as short as possible but will be more than happy to discuss this further.
About the pages:
1) Simple to do, logins and user management
2) From what I understand, you have an excel sheet of transfer rates for specific routes/destinations and you need that displayed, please correct me if I'm wrong
3) Sure, payment gateways may be a bit tricky, you will have to tell me upfront what you want to use and support (Paypal, Credit Cards, etc)
4) Not much to say, easy to add
5) Not tracking drivers makes this far easier. About the admins, I'm guessing they will have their own private web interface, an admin panel where they handle all of that.
6) Instant messaging, sure. About the calling, I'm guessing just give the company number and ring it, nothing special.
7) I'm not 100% sure on how notifications could be handled, but shouldn't be hard. Coupons are fine.
This is my current bid and I think that its fine.
800AUD and a full month of development, honestly it should take less time but just to be on the safe side.
By running costs I presume you mean server hosting, upkeep and all of that, shouldn't be more than ~5USD a month for a server that can handle this without a problem.
I'd suggest doing the backend in C#, so just a server that can run it. Can be Linux
The app can be a browser host (non-native), something like Electron for PC, that would make it easily cross-platform
I cant write more here, char limit so please ask if you need more info
Thanks