I'm pretty low maintenance also, I guess.
I get my hair cut 3-4 times a year, but my aunt is a stylist and won't take any payment for it. When I lived farther from her I just went to a $20 place 3-4 times a year. I generally color my own hair (not with kits from the store but with products from Sally Beauty) even though my aunt will do it for me for free.
No gym membership anymore...when the weather is nice I'd much rather be outside walking or hiking, and I found it was a waste of money the rest of the year because I was so bored there I wasn't using it. It was 45/month for two of us.
I used to be a nail biter. I've done artificial nails a few times but they ruin your real ones, so once I was able to quit biting I just spend a little on good tools (glass nail file, a good strengthener, etc) and just maintain my own. I buy polish sometimes online at wholesale prices too - I probably spend less than $50/year on this. I'm not crazy about having other people's hands on my feet or massaging me either, so I don't spend anything on pedis or massages either.
Tanning's out of the question for me...even if it weren't so bad for your skin, I'm so pale I only burn and it would be asking for serious trouble. Generally I embrace my paleness but sometimes I use a sunless tanning lotion by Queen Helene, which is pretty inexpensive.
I don't do Weight Watchers, but my health insurance through work does have a program where you can sign up totally free (for the in person meetings, or online) and they pay your fees for it. If I have a hard time after the baby, I might do that, but it wouldn't cost me any fees.
I do like nice handmade soaps and body products, and I wear some makeup - I would say my monthly average total for all upkeep throughout the year including toiletries, makeup, lotions, sunscreen, etc would probably be about $50/month or less.
I am interested in laser hair removal though, so I wouldn't have to shave - it sounds expensive but maybe I can point out to DH how relatively little I spend on myself the rest of the time and make a case for it.
