NSMutableArray *array = [[NSMutableArray alloc] init];
NSNumber *num = [NSNumber numberWithFloat:5.10f];
[array addObject:num];

for (NSNumber *aNumber in array) {

self.textView.text = [NSString stringWithFormat:@"%@"
[NSNumberFormatter localizedStringFromNumber:aNumber
numberStyle:NSNumberFormatterCurrencyStyle]];

}

self.textView.text = [NSString stringWithFormat:@"%@", [array componentsJoinedByString:@", "]];