Hi cligan
Had a quick peak at your profile, and I see you're quite a new and youthful poster - welcome to MN!
I think when you don't have a lot of money it's really hard to save, but it's very important to get into the habit - even if it's very small amounts.
I think you need to sit down with your partner and think hard about a 'budget' - what are the absolute essentials? - Rent, bills, food, baby items etc.
Look at your receipts over the course of a month or two and write down how much you REALLY spend on these things (it will probably be more than you estimate!)
Then work out how much this is a week/month etc and put this 'aside' - that might be in a separate jar/tin or bank account - consider it 'untouchable' except for paying for the essentials it's meant for.
The you should add othe 'budget lines' so for 'treats' or 'clothes' etc.
When you spend money, what do you spend it on?
Is there some way you can replace what you're spending it on with a cheaper alternative e.g. getting a DVD instead of going to the cinema?
I know it's a terribly easy thing to say, but if at all possible, try to live within your means, and don't be tempted to run up huge credit card bills in the hope that tomorrow some extra cash will just turn up...
There are some really good websites with advice about budgeting and saving money etc - try MoneySavingExpert.com.
Good luck
x