The last time I looked it's 2008. Accounting software is unlike other software in that governments worldwide make changes all the time in relation to tax and how people are employed and paid. So starting a project based on QuickBooks 2004 isn't a good start. A QuickBooks 2004 format company file will be converted by QuickBooks 2008 to the new format when it's opened and there's no backward converter. In addition QuickBooks 2008 (UK version) is a lot different to QuickBooks 2004 (UK version) even when it comes down to the column names seen in QODBC. So before you start, everyone has to get on the same page.
Also, in my experience there's no such thing as a one off application. Sooner or later your going to have to fix, modify, change or enhance your application because of a new business requirement, unless you plan on leaving the country or you've got a big rock you can hide under. On going work requires the developer to have their own QODBC license. QODBC is licensed to each computer it is used on.
As far as what you can do when the 30 day evaluation runs out, well you can still use a QuickBooks Sample Company file even with an expired evaluation, you just can't use a real company file. | 
