You could save a chunk of cash by switching plans, but make sure you understand all of the details by reading the fine print and asking questions. Thinkstock By Lisa Gerstner, Contributing Editor From Kiplinger's Personal Finance, April 2016 Lease a phone for a dollar a month! Switch carriers and slice your bill in half! The wireless companies push promotions to entice new customers to their plans or to encourage current customers to try something new. Here's what you need to know.See Also: Best Phone Plans for Every Type of User If you’re getting a temporary rate on a phone or service plan, find out what the terms will be once the deal expires. When the latest iPhone was released last fall, for example, Sprint let new or current customers trade in a phone and lease a 16GB iPhone 6s for a bargain $15 a month (or as little as $1 monthly for 21 months if you traded in an iPhone 6). But if customers trade up to the next iPhone, the rate rises to $22 a month for the remainder of the lease; after the lease expires, the rate stays at $22 on a month-to-month basis until the next phone upgrade or purchase. Carriers regularly offer to pay up to several hundred dollars to cover the remainder of your device payment plan (or an early-termination fee, if you still have a two-year contract) when you switch to their network. But such deals come with stipulations. To qualify, you typically have to trade in your current phone in good condition and lease or buy a phone from the new carrier. And you may be eligible only if you’re moving from one of the major carriers. Before you switch to a new carrier, investigate its network coverage in your region; a discount isn’t very satisfying if your service is spotty. Ask neighbors, coworkers and friends about their experiences, and check the map at www.rootmetrics.com to compare performance among carriers in your area.