FYI, the answer above suggesting the use of DAAttributedStringUtils and DAAttributedLabel didn't mention that these are convenience classes for the use of NSAttributedString. They make formatting NSAttributedString instances a little easier. As an example, here's how to do the same formatting described about by HAS using DAAttributedStringUtils:
float finalPrice = 34.99, shipping = 4.99;
// Setup the formatter
DAAttributedStringFormatter* formatter = [[DAAttributedStringFormatter alloc] init];
formatter.defaultFontFamily = @"Georgia";
formatter.defaultFontSize = 12.0f;
formatter.colors = @[ [UIColor blackColor], [UIColor redColor] ];
NSAttributedString* attrStr = [formatter formatString:@"%0C%0FRed Courier Text %1C%1FBlue Arial Text %0CRed Arial Text"];
// setup base strings
NSString *finalStr = @"Some Text. ";
NSString *shippingAttributed = [NSString stringWithFormat:@"%%B%%1C$%.2f%%b%%c", shipping];
NSString *middleText0 = @"Final price including ";
NSString *middleText1 = @" Shipping and all discount: ";
NSString *finalPriceAttributed = [NSString stringWithFormat:@"%%B%%1C$%.2f%%b%%c", finalPrice];
// Format the strings
self.label.attributedText = [formatter formatString:[NSString stringWithFormat:@"%@%@%%B%%1C%@%%b%%c%@%%B%%1C%@", finalStr, shippingAttributed, middleText0, middleText1, finalPriceAttributed];
Somewhat less code, and I think easier to understand. FYI, the formatter string in the last line contains codes that are used to modify the format of portions of the string. Those codes use double percents (