I always had a problem lying. I never knew an excuse to say while trying to get something. I never knew what to say if they asked for the receipt. I would stutter, say "um" and get nervous a lot. I created a list of ideas on an excuse that you can use so you do not have to provide a receipt.
Here are some excuses you can use, ill add more later in the future.
Of course this isn't always going to work 100% but it is possible and works most of the time, maybe you can get some ideas off this and maybe you can be creative and make an advanced excuse that is always 100% guarantee to work..