I come with a rounded up exp of development, test and have played role of program / project manager so understand the timeline.
I have over 10 years of pure development exp in PERL - developed migration utilities, products, scrapers, web sites.
The way I would approach is:
Day 1 : Development of the application
Day 2: Test Scripts and debugging
Day 3: Delivery and user acceptance
I can support for the application for any enhancement for 1 week.
If you dont like the application - dont pay !