I am currently using PayPal's invoicing feature...which I really like because I can create product and service descriptions and pricing and save them, create templates, and I don't have to collect credit card information for payment.
I have started using it to do "proposals" too for all of those reasons. The problem I am having is that if I want to provide client with options, I have to include them all on the invoice, and they are all calculated in the final total. Then, after the client makes their choices, I have to delete the ones they don't want and issue a new invoice for payment.
It works for simple jobs, but can get messy for larger ones. I really need to send them a proposal first, but my current options are manual.
I wish there was a proposal plugin for Wordpress that will integrate with PayPal and accept subscription payments. Is there anything like that anywhere?