Alexa von Tobel is the founder and CEO of LearnVest.

I spend only money I know will move the meter for the business. I always think, If I were paying for this out of my own wallet, would I buy it? That one filter gives you your answer.

That's not to say you should be as cheap as possible, but it helps you focus on where you're actually making an investment. Give me the cheapest business card that exists, but get my team the best technology. Sure, we could have free lunch five days a week-;or should everyone get an iPad?

Would you rather have random taco night, or would you rather have a bonus? It's easy as a company gets bigger to spend, spend, spend, but make sure where dollars go is where they'll have the biggest impact.

As told to Issie Lapowsky