There are two main questions when we negotiate: How do we do it well? When is it appropriate?We’ve got #1 covered with our start-to-finish negotiating 101 guide for asking for more at work, and 11 tips from experts and readers on bargaining at stores and on the phone.That leaves us with #2: Most of us know we’re supposed to negotiate when it comes to buying a house or a car, but how about at the dry cleaner? Or when we’re on the phone with our cell phone provider? Hesitate no longer.Read on for five unexpected costs you should negotiate, and how:1. Cable and Cell Phone BillsWhen to negotiate: You’ll be most successful if you try to negotiate with your current carrier near the end of your contract, when they’re more desperate to keep you. Remember: It’s far harder for a company to acquire new customers than to keep the ones it has. Go into the negotiation after doing competitive research on sites like Billshrink and Lowermybills to know what they’re offering new customers, versus what they’re offering with the plan you have.MORE FROM LEARN VEST: Negotiating 101How: Here is a nine-step process for negotiating your phone bill, including a sample script for your phone call–all the same principles apply to negotiating your cable bill. If the first rep you speak with says she can’t do anything for you, ask to speak to someone in the customer cancellation department. That’s where the customer service agents have real power. If they transfer you to a “retention department,” know you’ve got the upper hand, since that’s the department trained to offer deals to keep you.2. Furniture and MattressesWhen to negotiate: When it comes to mattresses, always try. Don’t be shy about asking for special deals, like a price reduction, free shipping or a complimentary box spring. Mattress manufactures set minimum prices that they allow retailers to sell their mattresses at, so a store either has to price them at that minimum or overprice them and negotiate. Most of the larger chains price them at the minimum, so if a store is willing to negotiate, odds are they’re overpriced.When it comes to other types of furniture, you’ll often have more luck when you can pay in cash, or when you’re at a family-owned shop rather than a big chain. Smaller shops mean you can negotiate straight with the owners, rather than dealing with a salesperson who doesn’t have much power to budge.How: Furniture is often sold at 80% markup, letting stores give the impression that they’re selling cheaply when they host sales–but even during a sale, they’re still usually making a huge margin. So, try to negotiate past the discounted price. If all else fails, SmartMoney suggests, write down the product number: “You might be able to search online for other retailers who sell the same piece at a lower price.”3. Medical BillsWhen to negotiate: When you receive a bill from your doctor or the hospital that doesn’t look quite right, or seems much higher than you expected. Did you get charged for something your insurance was supposed to cover? Don’t waste your time if you’re only facing a $25 copay–but if you are looking at a steep bill, it’s worth negotiating. Some doctors will even provide reduced rates if you fill out a hardship waiver–to learn more, ask the billing person at the hospital or your doctor’s office.How: You can have a go at it yourself by calling your doctor or the hospital directly, though this may be time-consuming and you may have to persevere through apologies about set-in-stone payment rates, when in fact many rates are flexible. If you call up on your own, just hold firm and explain why you either deserve to pay a lower rate (the billing person messed up, the doctor’s office didn’t sufficiently explain the fees) or why you can’t.Another option is to use a medical negotiation service, which does all that for you. Generally, these services charge a percentage of your savings, so you don’t have to pay if they don’t get you anything back.MORE FROM LEARN VEST: Guide To Kids’ Eye Care4. Vacation DaysWhen to negotiate: The very best time to negotiate for vacation days is before you start a new job. If your employer can’t give you the salary you want, ask for something other than money, like more time off. In a market full of pay freezes and tough job-hunting, employers might have more wiggle room with perks like vacation, flex scheduling, continuing ed benefits and even tuition reimbursement, since these perks are often less costly to them.How: According to Jean Baur, senior consultant at Lee Hecht Harrison and author of “Eliminated! Now What? Finding Your Way from Job-Loss Crisis to Career Resilience,” it really has to do with company structure. A hiring manager can’t bring in a middle manager at a higher salary than the senior managers, so asking for a sign-on bonus or additional vacation days may be more successful. It’s often a lot easier to get an extra week of vacation than it is to raise the base salary by $10,000.Start by researching trends in your field and region, so you have a sense of what perks could be reasonable to expect. Also address how your perk can benefit, or at least not negatively affect, the company. For example, if you want more time off, come up with how your workload will be covered.5. Gym MembershipsWhen to negotiate: You’ll save the most when your gym offers the biggest promotions, usually around the new year. As The New York Times puts it, “Gyms … often operate a bit like airlines or car dealerships; people working out next to each other may be paying different rates depending on when they signed up and other factors. Those who sign up in slower seasons or around the New Year when the most promotions are offered, for instance, tend to pay less than those who sign up during other times of the year, according to industry sources.”How: Pamela Kufahl, editor of Club Industry magazine, recommends research as the first step. Look at the websites of the clubs in your area to narrow down your choices, and pay them a visit–while you’re there, ask for a free one or two-week pass. Once you know where you want to go, ask friends who are members what they pay, or check online message boards to find other people’s rates. Also, check with your employer or guidance counselor to see about deals offered through work or school.MORE FROM LEARN VEST: Is Kids’ Food As Healthy As It’s Advertised To Be?Then take that intel to your preferred gym. If they quote you a rate higher than what you know other people pay there or what you could pay at a similar gym, Kufahl suggests, “Say ‘hey, my friend was offered this rate two months ago, can you match it?’ or ‘I checked out New York Sports Club and they are offering this rate, could you match it?’” She also recommends asking about promotional rates coming up and whether the staff can waive initiation fees. If the answer is still no, try asking for other perks instead, like free personal training sessions.