T-Mobile has just announced that it plans to end one of the last remaining barriers to get people to switch over to its network: those pesky early termination fees. At its fourth Uncarrier event at CES 2014, the carrier announced that starting tomorrow, customers from the three other competing national carriers can trade in eligible handsets to any T-Mobile location, switch over and get an instant credit of up to $300, which should be able to cover the bulk of most ETFs.