1. A seamstress who knows your body and will tell you like it is. I once bought a bridesmaid dress for $300, then proceeded to spend $200 in alterations. I praise the Lord for Linda, the seamstress I now see anytime I need something done. My wedding dress alterations are going to cost less than I've spent with other seamstresses on bridesmaid dresses.
When I was there this week, a hem fell out of my skirt while we were talking (what are the chances!?) so she had me take it off and fixed it on the spot for free. And! Last time I took her a dress, she told me it was too loose and long and didn't flatter me. To have this kind of rapport and good prices has saved me a lot of money - and headaches.
2. An HSA (or similar medical-only fund). My night guard broke recently broke (the sexier side of my sleep habits) and insurance didn't cover a new one. That $600 bill hurt a lot less when I could pull from my HSA. After a few months, you don't even notice the money coming out of your paycheck, either.
3. An affordable dry cleaner. Just like a seamstress, you can spend a lot of money on a dry cleaner if you don't shop around. After moving to Midtown, I discovered Sig Samuel's, which is easily the best dry cleaner I've ever experienced. They know my name, are kind and have excellent rates.
I once left work late and knew I wouldn't make it by 7. I called to see if anyone would be there a few minutes after and they said they'd wait for me to arrive. That is the kind of service you need when you're in a jam!
4. A go to gift. Throughout your 20s, there are about a million reasons to give small, unexpected gifts (think engagement & hostess, to name a few). I used to scramble when a friend got engaged, spending an arm and a leg on something at the last minute. Now, I have a few Etsy shops I always buy gifts from that I know are affordable, reliable and make sweet gifts.