Tin is one of the cheapest metals around. Although it comes with very competitive prices, you should not evaluate your purchase of tin roofing solely based on the price tag. If you do, you might end up installing tin roofing that might not be suitable for your home.
For a tin roof to be effective, it must be insulated to keep the noise level down when rain falls. Unlike other thicker roofing materials, tin roofing makes a lot of noise during a wet day. Sufficient layers of soundproofing material should be placed directly under the tin roof to absorb most of the noise. This is insulation will also double up to keep the house cool during summer and warm during winter. With the proper installation, your tin roof will not sound like a drum circus every time it rains.
Tin roofs are also able to withstand the environment very well. Rainwater will not erode a tin roof because tin is not corroded by water and salt. Stronger metals like steel would start to develop rust after too many wet days. The only thing that would start to corrode tin is acid. If you live close to an industrial, then be aware of the acidity of the rain because this could corrode your tin roof.
Basically, the two main strengths of a tin roof are its cheap price and excellent durability against the environment. These two factors are what keep tin roofs around until today. There is one more thing to consider before getting a tin roof though. If your area experiences extreme weather conditions such as hurricane force winds, then a tin roof is absolutely out of the question. Extremely strong winds would rip the tin roofing off your house quite easily. But then again, if you go through a really bad hurricane, any type of roofing would be blown away.