I have a PAYE job as my regular 9-5. But in the past few months I have started designing yoga mats and selling them on ESTY using printify to print and dispatch. You can have a gross income of £1000 before you need to do a self assessment form. So far I have made around £300 profit since launching in September. In terms of the £1000 obviously I include Esty fees in this but what about printify and the underlying costs of the mats etc? I am really the middle lady, the customer requests one of my designs from my shop and printify fullfills.