During development of ParrotBot, I've ran into many issues in terms of debugging, design and integration. In the chat room, I've received lots of support that has helped me greatly, so that I could continue the project, with ease.
However, I've started wondering whether I could possibly be charged for this "support." Having forked an open source project, could I be charged for this, being the developer of the forked version?
Not after you've been given it.
When giving you support, the supporter (the dev in this case) has essentially said "I'm happy with the payment I'm getting for this." If the payment is nothing, fine. They're happy.
They can't suddenly change their mind after giving you the support and say "hey pay me for that now" - it'd be like someone giving you a present and saying 3 months later, "hey you should pay me back" - you wouldn't stand for it, and they have no legal standpoint for it. It's already been gifted.
What they can do is refuse you support until you pay. That's OK under open/free licenses, and it's them wanting a support contract: in return for their help, you give them money.
Yes and no:
Yes if....
You have previously agreed to pay them for their service. For example if you went to the people helping you and said "I will give you $20 to help me". Them agreeing to help you under those conditions ( for $20) is a contract between you and the person helping you, you therefore need to pay him / her.
No if...
They provide support and then later demand you pay them for helping you. Under this situation you never agreed to pay them and they provided a service. However you can CHOOSE to pay them, but this is not necessary.
