Simply asking for a better deal is one of the most underused tools in our financial arsenal, and it's one that rarely even crosses our minds. Most people don't think to negotiate their credit card bills, interest rates, hospital bills, or even their own salary — but the numbers we receive are rarely a hard line, a lesson I wish I had learned earlier in life.

Staring down a massive ER bill, I sat with my friend to commiserate over my financial situation. I was saddled with thousands of dollars in medical expenses, over $2,000 on one bill alone. As a mother, my friend was no stranger to the plight of unexpected medical expenses — but instead of offering sympathy, she offered me advice: Barter with the billing office.

"You can do that?" I asked suspiciously.

"Yes, but you have to ask. They won't give you anything unless you ask."

I still wasn't convinced this was something just anyone could do. But what did I have to lose? The worst that could happen was I'd be stuck with my original bill, so I gave it a shot. When I asked if there were any discounts I was eligible for, a few hundred dollars were knocked off my bill in a matter of minutes. It was like earning a $100-per-minute rate for having a slightly uncomfortable phone call.

It turns out the "just ask" policy doesn't only apply to medical bills (though that was certainly an eye-opener for me). The same applies to getting a lower annual percentage rate on your credit card, or even getting late fees removed. Overdraft your bank account? Ask to have the fee removed. Forgot to cancel after a 30-day free trial of something? Ask to opt out and get a refund. A lot of financial doors are ready to open up for you if you simply muster up the courage to ask.

Of course, none of these companies will tell you there are discounts and get-out-of-jail-free cards available upon request. It would be bad business to do so. But the truth is, customer service still counts, and companies from banks to retailers to medical centers want to stay in your good graces. You can reduce your debts, get better rates, receive unexpected perks, and more if you are willing to put yourself out there a little bit.

Simply asking is also a severely underused tactic in the workplace. When was the last time you negotiated your salary? How about your benefits — your paid time off, your ability to work from home, your bonuses, even your gym membership? Maybe it's time to revisit those numbers.

A study from Payscale, which surveyed 30,000 workers, found only 43 percent had ever asked for a raise. Seventy-five percent of those people received one. Not everyone who asked got the full amount they asked for, and yes, some didn't get a raise at all, but the odds were still very favorable. Especially when you compare them to the 57 percent of workers who didn't ask for a raise. While some still received raises based on time or merit without asking, the vast majority simply skipped out on asking because it made them uncomfortable.

While negotiating isn't always a "fun" skill to learn, it's certainly worth wading through the awkwardness to learn how to do it properly. Especially at the beginning of your career, it is crucial to learn to ask for more, because if you don't negotiate your salary right out the gate, you are leaving huge earning potential on the table for the rest of your life. Even modest increases lead to much better future earning potential since your raises, bonuses, and even future job offers will be based off of that initial salary. If the thought of asking for more makes you cringe, it's likely that the amount you will lose out on in the long run will make you even more uncomfortable.

In an interview with NPR, Linda Babcock, an economist and professor at Carnegie Mellon University, says she tells her graduate students that by not negotiating at the beginning of their careers, they are effectively "leaving anywhere between $1 million to $1.5 million on the table in lost earnings over their lifetime." That's a big reward for having a simple conversation.

While asking for a better deal may feel foreign at first, it's a skill that's well worth honing. You'll earn more, you'll owe less, and over the long run, it will almost certainly change your life.