You're about to learn the secret sauce of SpendPal. If you don't have enough money in your Clothing Category, and you REALLY want that new suit...
First, look through your other Categories. Is there another Category that is less important to you than the suit? Perhaps there's extra money in your Restaurants Category, maybe there is a few dollars in your Fun Money Category... If you find a Category with extra money you don't need, then feel free to steal the money out of that Category and go get that suit you want!
If, after scanning through all of your other Categories, you can't find anything else you're willing to give up, borrow a suit this time, or wait a few weeks and buy the suit later.
You'll have peace of mind knowing that your money is all being used for things that are more important to you and you'll save yourself from buying something you'd later regret!