This is a guest post from social-media maven Laura Roeder. Laura first told me this story in January, and I used it as the basis for one of my columns for Entrepreneur magazine. Over lunch recently, she offered to write a guest post about her experience. I told her I’d be glad to share it.

Secret phone plans? No contracts? Unadvertised payment plans with no interest? These are all available. But you’ll never know until you ask.

I recently decided to switch carriers to T-Mobile, so I jumped on their website to start doing the math of the different plans that they offered.

Just when I felt I couldn’t possibly calculate the details of one more plan, I came across a section on the website that featured plans without contracts. This section was buried; in fact, I had to be logged on a friend’s account who was already a customer to be able to see the plans at all.

I was confused by what I found. The plans without the contracts had a lower monthly cost than the plans with contracts. I figured there would be a premium fee to not be locked in to a two-year contract, but I was seeing just the opposite.

I went into a T-Mobile store and asked about the plans. They didn’t show me any plans without a long contract. So I asked about a no-contract plan but the sales person was dismissive, saying “but you’re going to have to pay full pay price for the phone.”

I insisted that I wanted to see the plan anyway, and he went to the back of the store to dig up the brochure for me.

The exact same plan without a contract was \$110 a month instead of \$140 a month, for a savings of \$360 a year. I looked for the catch, but the only catch was the no-contract plan didn’t offer the usual discount on a new phone.

The phone I wanted to buy retailed at \$500, but cost just \$200 with a contract. (That’s a savings of \$300, in case your math muscles aren’t working.) I quickly did the math: I could save \$360 per year without a contract, but would have to pay \$300 more for the phone. That still left me with \$60 in my pocket for not having a contract, meaning no insane fees if I wanted to leave the contract or switch carriers. Plus, everything after the first year was pure “profit”.

I soon learned from the sales associate that apparently no one had ever bought a phone outright and taken them up on the no-contract plan. It’s not advertised and therefore usually not asked about. They just assume that no one will want to pay more now in order to save later.

The sales associate couldn’t believe that I was “baller” enough (his exact words) to pay \$500 for a phone — even though I was actually saving money within a year. He even asked me what I did for a living to be able to afford such an extravagance!

It gets better. When he went to ring up the phone, he asked me if I wanted a payment plan. I asked for the details and he told me that they offer no-interest payment plans so that people don’t have to shell out the full cost outright. Meaning that if you didn’t have the \$500 for the phone, you could still save money by going with a no-contract plan!