Hello all, I've only recently joined so bear with me!

I'm currently gaming on a Nvidia 750 Ti and it's really struggling with my new QHD/1440p monitor. I want to sell it and upgrade - but concerned if it will be taxable income? I received it as a gift a while back so didn't pay anything for it. I've looked at this tax tool (salary-calculator.org.uk) and it says my income will go into taxable amounts (part time work/student) if I do sell it. Should I be worrying?