I'm about the most undisciplined person out there so I can't believe I'm going to say this, but I really agree with blue october about needing the structure of work (even if I skip lots...) Getting out of the house or even out of bed can be really hard, but I find it easier if I have to be somewhere at a particular time.
I don't have the spending issues, but a friend who is a compulsive shopper, only buys things you can return, then later in the week takes them back! It's really funny, but saves heaps!!!!