T-Mobile is the fourth largest GSM operator in Poland, with the smallest subscriber base. It owns a little less than 25% of the total number of subscribers in the country. It is believed that T-Mobile has the best 2G coverage in Poland, which covers almost the entire territory of the country. T-Mobile SIM cards are a good choice for working in the field of voice termination, if you choose the most favorable tariff plan..
Prepaid SIM cards from the T-Mobile operator are sold for 5 zł (this is approximately $1.3). They are called T-Mobile Na Karte. After activating the card, the subscriber can immediately take advantage of the Bez Limitu tariff plan, which is valid for 5 days. Within 5 days, you can call any number for free, as well as send SMS. After expiration of the welcome tariff plan, a monthly payment is required to be made.
T-Mobile Na Karte is great for voip call termination business. With an unlimited tariff plan, connected by default, a minute of a call will cost only $0.003 (if you terminate 5 hours a day). Earnings on traffic landing can make $50 and more from one GSM gateway channel.
5 days after the SIM card activation the tariff plan is automatically renewed for 30 zł per month (about $7.7). For termination, 5 days for one SIM-card will be enough; during this time you can land a large amount of traffic. Given that the cost of the cards is low ($1.3), you don't have to wait for automatic connection to a more expensive tariff plan but buy a new starting plan.