iOSから直接AWSのCloudWatch APIを叩いて利用料金データを取得してみたよ ref: http://qiita.com/morizotter/items/70f83f1e75ebc70be94c

file0.m

#import "ACSViewController.h"
#import <AWSCloudWatch/AWSCloudWatch.h>

@interface ACSViewController ()

@end

@implementation ACSViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
}

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];

    [self getData];
}

- (void)getData
{
    AmazonCloudWatchClient *client =
    [[AmazonCloudWatchClient alloc] initWithAccessKey:@"YOUR_ACCESS_KEY_ID"
                                        withSecretKey:@"YOUR_SECRET_ACCESS_KEY"];

    CloudWatchDimension *dimension = [[CloudWatchDimension alloc] init];
    dimension.name = @"Currency";
    dimension.value = @"USD";
    NSDate *startDate = [NSDate dateWithTimeInterval:-60 * 60 * 24 sinceDate:[NSDate date]];
    NSDate *endDate = [NSDate date];

    CloudWatchGetMetricStatisticsRequest *request = [[CloudWatchGetMetricStatisticsRequest alloc] init];
    request.metricName = @"EstimatedCharges";
    request.namespace = @"AWS/Billing";
    request.statistics = @[@"Sum", @"Average", @"Minimum", @"Maximum"].mutableCopy;
    request.startTime = startDate;
    request.endTime = endDate;
    request.period = @60;
    [request addDimension:dimension];

    CloudWatchGetMetricStatisticsResponse *response = [client getMetricStatistics:request];

    if (response.error) {
        NSLog(@"error: %@", response.error);
        return;
    }

    NSLog(@"label: %@\ndata points: %@", response.label, response.datapoints);
}

@end