You and your husband are not taking care of yourselves, or each other. He might be your "best friend" but he isn't behaving like one right now. Hanging up on you? Approving your minor expenditures? Calling you names?
He - and you - should be viewing your depression with concern and compassion. Depression can be (and usually is) a chemical imbalance, which can be treated with drugs or ameliorated through nutritional supplementation - I've done both. When I was on meds, I didn't have my super low "lows" but I didn't have a lot of "highs" or joy either. I went off my meds but did it too quickly, and my symptoms returned. So I went back on and then, with my doctor, did an organized, planned weaning-off (gradually decreasing dosages, then going to 2 days on/1 day off, then alternate days, etc. I wonder if you went off too quickly while you were also undergoing job changes and adding in a long commute? I have been able to manage since because I added in comprehensive nutrition, and I've stayed very stable ever since (and I have more energy, go to the gym, etc. which help offset depression). A lot of people don't realize how absolutely exhausting depression is, how it saps you of your energy and zest for life.
That said, you also have things in your home environment that are contributing to your depression. That doesn't mean they are causing them, but it does mean they are harder to deal with. And fixing those may or may not "fix" your depression - probably not. But you definitely sound exhausted, mentally and physically. Of course you absolutely need to get some "me" time - you are a woman, not just a wife, mother and employee. So instead of asking permission to do something and having your husband throw a fit about having to be a parent, I say go ahead and do what you need. Definitely join the Sisterhood and do a few activities, giving your husband some time alone with the children. Kids benefit from knowing there are 2 parents who are equally capable of making breakfast or driving a carpool or running off a load of laundry.
However, you two also need some couple time, and that means finding some child care for the kids and figuring out a way to have a date night (or a date afternoon on a Sunday, whatever). If you can't afford a sitter, try to trade off child care with another couple (or 2 couples if you need to send each child to a home with a child his/her age). The exchange will allow each kid to have some play time with a friend and give the adults some adult time. After having a few extra kids in your home, your husband may feel that caring for your 2 is no big deal. The 13 year old is probably fairly self-sufficient and only the 3 year old needs constant supervision.
If you can't afford a vacation, you can certainly afford a picnic or a walk in a nature preserve, a stroll on a beach, an afternoon at a museum or browsing through art galleries, visiting antique shops (even if you don't purchase anything), going to yard sales, going to a free outdoor concert, anything that would be diverting. Your husband might find he has some additional interests (including you) and doesn't need to just sit at home all the time. It's not an insult to say "My whole life is NOT this family and I need to take care of myself in order to take care of them." That goes for him and for you. If his family is so important to him, he won't mind spending time with the children in it, deepening his relationship with them and letting his wife get some stress relief.
You can either stand up to him and figure the $100 is well-spent on the retreat, or follow the suggestion below to squirrel away $2 a week so you can afford it next year. But taking time for introspection and self-awareness is very much in keeping with the high holidays, and it's how we Jews spend the month before Rosh Hashanah in order to restore ourselves and be "written and sealed in the book of life" for a sweet new year. We reinvent ourselves, we look at what we've done in the past year that hasn't been productive, and we set a path for a better year next year.
When my son was little, I had 2 "me" days a month - I'd take my son to preschool and keep on going. My husband picked him up, gave him lunch, played and put him down for his nap, then did some work. I went to lunch, to the library, to a movie alone (tons of fun!), browsed stores, etc. - no agenda sometimes, just let the car go where it wanted. It saved my sanity. And my son and husband have an incredible bond from this time together. My son knows that men do laundry and dishes and give baths and run the household just fine - he's grown up to be a better man because of it. And your daughter will choose a better partner for herself if she sees both of her parents as whole and happy humans.