If you are in twenties or early thirties and remain single, earn $3,000 after tax per month, you will probably save $1,000 if you, let's say, spend $500 to $800 on rental, a guest bedroom in a shared house/apartment, $500 on food, $50 on utilities, $150 on phone/internet bills, $400 on commuting costs or gas/maintainance if you have a used car, $200 on occasional entertainment or others. This $1,000 savings will allow you to invest or place a house down payment when time is ripe. Is this possible based on where you live ?
Actually it all depends on your expenses,cost of living and how much you are earning or getting paid.
Some would really find it hard to save one third of their earnings since they have so much on their plate even in the age bracket that you have given.
There are also times that people tend to spend their money on things that would help them relax or relieve some stress from their work and believe me those expenses are needed in order to survive or be motivated.