This was the cost to buy up earlier this year:
http://www.usairways.com/awa/content...00361_03122008
Elevate your status with US
Buy up to Preferred fee*
1 - 1,999
1 - 2
$229
2,000 - 4,999
3 - 6
$379
5,000 - 9,999
7 - 11
$529
10,000 - 14,999
12 - 18
$829
15,000 - 24,999
19 - 29
$1,050
25,000 - 49,999
30 - 59
$2,500
50,000 - 74,999
60 - 89
$5,000
75,000 - 99,999
90 - 119
$7,500
100,000
120
$10,000