I would second this.
A 1x30 grinder will be an improvement on what you are using now.
I think I got my old 1x30 5 inch disk combo for under 60.
Used it for years.
For sure, I would suggest more practice before selling.
You can hand file bevels straighter than what you are doing right now.
Here is the first knife I attempted (before heat treat) ...all hand filing and the pin holes drilled by hand with a hand crank drill!!)
A 2x72 belt sander is a huge step up in capability, and in my opinion, what you should be saving up for. (Once you get tired of the 1x30.
2x72 Variable speed...
I am no expert knife maker. Just a tinker. But I've been collecting and using customs for over 30 years.
I've made 6 knives.
Two forged.
I remember a few years ago, a hobbiest maker started posting his knives here.
He had years of custom knife buying and using.
He got a lot of critique of his work, and one of the most helpful things said by one of the guys here was something to the effect of "look at your nice custom knives you own and use every day..... compare that to your own grinds...lines....finish....you know what a good knife looks and feels like. Keep working until your knives start to look like knives you would buy with your own money.
Here is the 6th (most recent knife I have made).
This is my second attempt at forging.
That was a knife I felt was decent enough to give away to my Dad as a Christmas present.
Make sure your profile is filled out. Take advice...some local makers may be willing to help.
When I posted the first knife that I made with hand files and no power tools..one of the best living knife makers in the world offered to heat treat it for me, and gave me advice.. (I heat treated it my self ).
Work on getting even, straight bevels, and making comfortable handles with no gaps.