As far as internet service goes in Guatemala the most popular choice is Telgua. It is the largest telecommunications provider in the country, and although there are plenty of other options out there, Telgua seems to dominate the market.
Telgua offers a package that includes phone, TV, and internet for $60 a month. The TV plan is digital and includes 200 
channels, the digitial phone line has unlimited calls to other Telgua customers, as well as Claro lines. The internet speed is about 1MB down and 500K up, as done by a speed test. (I am not sure what the technical up/down are on the package, but those are the average speeds you will be receiving.
One of the plus sides of the Telgua plan is that you do not have to sign a contract. This makes it an attractive option for many. On the down side soliciting service and actually getting the line hooked up in your residence or office can be difficult. While they are the biggest company, the customer service can be pretty hit or miss.
There are a ton of other options as far as internet goes from the other major providers: Telefónica, Tigo, and Claro. Ask around to see what those in your area are doing as far as internet service goes and you will have a better idea of what will work for you.
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