I think it depends on how much you make, and how much you need to spend to get by.
If you aren't making bills, it's of no use to you to invest your money. Right now your main concern should be to get your bills taken care of.
That being said, if you are caught up on bills, then you should invest as much as you possibly can. Ideally, you will end up with more money in the end, and then you can use some of the excess to buy the things you went without earlier.
I'm a big fan of not being in debt over unnecessary items while you could be investing the money instead. That's why I would never suggest anybody buy a car on a loan. Sure, you might like having a nice car, but if you invested the same amount of money, then years later, you can buy the same car with cash, AND have extra money on top of that.
Sad now, happy later, and with money to spare.
