Can I claim postage

Hello, If i sell goods I make and as part of the order I receive I am paid postage, am I able to declare that as an expense on my tax return? for instance item costs £15, postage cost £3 - total paid is £18 - I declare my sale at £18 - can I claim the £3 as an expense? Thanks

Hi abb16ott,
Yes, you can claim postage expenses.
For a comprehensive guide to allowable Self-employed expenses, please refer to: 
Expenses if you're self-employed.
Thank you.