My headcanon on how well-off the servamps are
Sleepy Ash: Broke. He probably never found a job after becoming a Servamp. he couldn’t control his form before meeting Gear, and he pretty much did nothing aside from helping out the house when he lived with Gear. After killing St. Germain, he got sealed up and just recently woke up and bound with Mahiru. He and Mahiru both live off uncle Tooru’s salary.
Old Child: Filthy rich. Having been rich for his whole life, it’s difficult for him to change his life style, and he understands the importance of money and the benefits it gives. It’s impossible for him to find a job because of his five-year-old appearance, but that doesn’t stop him from using his subclasses to do investments for him. Using his centuries long experiences, he has accumulated a stunning amount of wealth under different aliases over time. I believe he still pays for food and accommodation for his special room in Tetsu’s hotel, along with other expenses like eating out or buying things he likes.
Doubt Doubt: Poor. He’s likely a priest when he was human, so he’s not very into material possessions. He also doesn’t really have a drive to live, so he doesn’t really care about money either. It’s not likely he ever had a job because of his overly quiet personality and tendency to constantly cover his face. Like Sleepy Ash, he was sealed up and then just spend time hunkering in the Alicein mansion basement after Kiriko broke his seal. He probably gets pocket money from Mikuni after they left the Alicein mansion, but he hardly spends any money aside from his hobby.
The Mother: Not very well-off. Not sure if she ever had a job before meeting her pervious Eve but probably didn’t go well because of her perpetual frown and death glares. After bonding with her previous Eve, she most likely helped out his business and had saved up some money. After bonding with Izuna, she lived off Izuna’s salary or just took up living in the C3 headquarter.
Lawless: Well-off. His slightly pampered personality and choosing celebrities as his Eves had indicated a comfortable life. He works part time to kill time, buy famous brands and stylish trinkets he likes, and to simply enjoy life. He also has Guildenstern to take care of his daily life and other subclasses to help him out when needed.
World End: It is canon that he’s completely broke and always waiting for someone to pay for him. All his money is spent on food, and is unfortunately still far from enough. Being able to eat and fight is the only thing important to him, so he often gets hired by criminal organizations or armies. Food is a huge cost for him, so it’s likely he gets paid with food instead of money, making him completely penniless.
All of Love: Living from paycheck to paycheck. He has been living in the Alicein mansion for centuries and has no money aside from the pocket money the Alicein family gives him. Food and accommodation are provided for him, but he often uses up his monthly pocket money too soon due to bad management. This is probably because money comes easy to him both when he was human and vampire, so he doesn’t really care much about it.
Tsubaki: Rich. Though he’s only been active in the recent years due to him being sealed up. It is unclear how he got the money, but he had accumulated enough wealth to disguise as a wealthy sponsor, reserve whole floors in a fancy hotel, feeding his most trusted subclasses, and conspire evil plans.