iPhone 5 T-Mobile

T-Mobile recently increased the price of the iPhone 5 by $50. (T-Mobile)

T-Mobile has quietly increased its price of the iPhone 5 by $50, raising the down payment to $149.99.

The Seattle-based carrier began selling the phone last month at $99.99 plus 24 payments of $20, for a total cost of $579.99, but now, T-Mobile is saying the initial $99.99 down payment was a promotional price that ended Sunday.

"We all know promotions are temporary," T-Mobile said in a statement.

AT&T, Verizon and Sprint charge $199 for the iPhone 5 with a two-year service contract.

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T-Mobile said the full price for the iPhone 5, now at $629.99, is still lower than purchasing an unlocked iPhone 5, which typically costs $650.

T-Mobile also said users can take advantage of another promotion it has going on that lets them trade in an old iPhone 4S or iPhone 4 to bring the down payment cost of a new iPhone 5 to $0. That promotion lasts until June 16, which is Father's Day.

The T-Mobile iPhone 5's new price now brings it in line with that of the Samsung Galaxy S 4, which also has a down payment of $149.99. Meanwhile, the HTC One, another top-of-the-line smartphone that came out in April, is still available with a down payment of $99.99.

The price increase may affect how many iPhone 5 units T-Mobile sells during the month of May and beyond. In April, T-Mobile announced it had sold 500,000 iPhone 5 units, but that was with the promotional price.

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