I use my own apps for qr code ;p but I did try scanlife to scan normal barcode and it work 40% of the time. I wish there was a good barcode(not qr code) scanner like there is on android, but hey, at least we have the lib from google.
I'd recommend to review the bar code readers in App World and make sure you pick one that reads all your needed bar code formats (UPC, EAN, Aztec, QR, Datamatrix, etc.)
While the QR Code scanner recommended above is good, it does *not* read anything other than QR codes (hence the name). Airline tickets are not QR Codes.
it is quite simple to scan a barcode, just add a barcode scanner on your mobile phone or other devices. but first you need to know what barcode are you going to scanner. if it is QR code, just use this QR code reader to scan codes for you.