There are lots of cheap kilts and sporrans on e-bay and I have bought a few myself. Some of them I have since passed on to others and some I continue to wear casually.
As you say you get what you pay for.
I've seen these Honour of Scotland kilts listed on e-bay but as far as I know the pattern is a fashion check rather than an officially recognised or registered tartan. I don't think the tartan is actually registered. (some of our tartan experts can maybe correct me on that).
It looks good on you for your music practice - wear it with pride.