Online customer form system

So I have a friend that works with events. She has the following requirements for a website: 1 - Her customers have to fill a form about the event they will have. This form is fairly large (lots of questions). 2 - Customers should be able to update the form as they go. 3 - She would like to be able to also edit/see the form as customers fill it in. 4 - Her budget is extremely small (like a couple dollars per month), but I am willing to help to get this going...

This what I already tried and had a look at: A - Google forms - Seems to fill all the requirements above, pain problems are:

• I have not figure out how to submit the form while in the middle of it. Imagine a customer has filled half of the thing and wants to just stop, currently AFAIK you have to go all the way to the last page to submit
• Second problem is that results are saved on a gigantic spreadsheet, which is not really friendly. The expected would be for her to go to the form and be able to see it filled (or some close representation of it).

B - Survey monkey - Seems awesome, but because of requirement 1 she would have to pay a subscription which runs at about 300 per year which is too much for her.

C - I had a look at having a website with django or meteor to host her form, but I would be happy if I did not need to code the whole thing up and maintain it.

So my question is. Does someone knows any kind of service that would fit her requirements or could point me to something that is half way there? I guess it is some kind of customer form keeping?