If at any point you find yourself running out of money, go visit the bank page. Here you can pick up your weekly allowance -- Basic players get $1000 and Star players $2000.
You can also open a second account, which will give you the same amount of money and breeding slots again. You can link your second account to your first on your "edit userinfo" page. Linking will allow you to easily transfer money, cats and tokens between the two accounts. Remember that you are not allowed to have more than two active accounts at a time! You also cannot link your account to someone else's, unless it's a shared account (the limit of two still applies).
This is the end of our quick tour through Pure Felinity. Of course, there is more to discover in-game, but this will hopefully help you get started. Make sure you read the extensive "Megaguide" threads on the help forums, or if they are too overwhelming at first, use the search function of your browser to look for a specific topic in these threads. The PFwiki is also being built up and improved all the time, and certainly worth having a look at if you need further help!