I was a SAHM for 9 years, just went back part time while the kids are in school.
I LOVED being a SAHM, but let me tell you, it was tougher than any high powered job I held beforehand!
You can do it, though, just take it one day at a time, remember that, like any other job, you don't start out being an expert, and to allow yourself time to learn and grow as a SAHM.
I recommend getting a TiVo, that way you can schedule watching TV, I found that I would watch too much at first because I didn't want to 'miss' shows.
Having them taped allowed me to get a lot of things done and then sit down, kick up my feet, and watch an episode of "America's Next Top Model" at 10:30 in the morning guilt free with a cup of tea while the babies napped.
And while I recognize that this may not be budgeting, you also have to remember that if you don't pamper yourself every now and then, you'll crack. I stay out of Target now, but man, I love my Tivo! I do my own pedicures (who's looking that closely at your toes, anyway?)
I try and do things that I enjoy, not that look good for the neighbors. That will get you every time, because there's always a richer SAHM out there. Stay away from the bored ones; they're trouble.
As I tell my husband, I'm not a Jones, I'm a Clampett!