Can build a system with personal login, giving acces to a platform with 3 administrative levels. Possible to create users with respective administrative level, new client, generate invoice for a client and save in server. Invoice is generated in pdf format and printable. Management of users and customers, and overview on all invoices created and incomes.
I am an intermidiate programer, I work for very low price my aim is to gain experience and if possible help you getting what you are searching for very low price. Domain and Host costs are at your own. I only provide the code and install it and configure inside your host. I set 30 days to be in safe zone, it might be much faster but without warranty.