The best alternatives to Proffer are AND.CO, QuickBill, and QuoteForm. If these 3 options don't work for you, we've listed a few more alternatives below.
What do you think of Proffer?
AssemblyAI— Speech-to-Text API with superhuman accuracy
From proposal to payment, AND.CO takes the headache out of freelancing, so you can get back to the work that drives you. Invoicing, Time Tracking, Payments, and More For Freelancers and Independent Contractors
QuoteForm creates an instant price quote for your clients. If you offer a service with multiple pricing options. You can change pricing based on conditions selected by users, which is difficult to do with other forms