Just as May’s 100% bonus on purchased miles ends, US Airways has a new deal for June: a 50% bonus on shared (transferred) miles.

The offer is just like the one US Airways had back in April but with a slight kicker: in addition to the bonus miles, they’re also waiving the $30 per-transaction fee.

Limited time offer: Give a 50% bonus and skip the processing fee when you Share Miles!
Now through June 30, 2013, when you share miles, you won’t pay the processing fee. Plus, you’ll give 50% more – up to 25,000 bonus miles.

Transferring miles costs a penny per mile. And they give you a 50% bonus. Which means if all you’re looking at is the cost to generate new miles, the price is 2.15 cents per mile (since there’s a 7.5% tax added on). For instance,

• Transferring 1000 miles generates 500 bonus miles at a cost of $10.75
• Transferring 50,000 miles generates 25,000 bonus miles at a cost of $537.50

All in all that’s more expensive a deal than when US Airways offers a 100% bonus on purchased miles (which comes to just under 1.9 cents per mile) and you have to also move miles from one account to another to take advantage. But that can also be a blessing to help clean out small balances in various accounts.

It’s especially nice that they waive the $30 per transaction fee, which makes cleaning out smaller balances more worthwhile. Although no matter how many transactions you do, the total bonus miles awarded under the promotion can’t exceed 25,000.