You don't say if you need zig-zag or straight stitch. And how many layers of denim do you want to go through? And is this going to be for occasional use or are you intending volume production?
Good questions. I might also consider electronics vs non-electronic in a basic new machine.
I have had quite good luck in finding older machines that are in very good condition - including Swiss made Elna from early 1970's ; German made Pfaff < from 1990's I think > Bernina seem to demand a premium in my area. My price range to purchase is ~ $ 25. - $ 50. One of the Elnas came in a beautiful sewing desk for $ 100. John T.
I bought my 195x Husqvarna at an estate sale for $3.00 and later on found a box of genuine Husqvarna attachments at a rummage sale for $1.00. It has oilite bearings (no oiling required) and a stump-pulling low gear. Uses Singer bobbins and probably attachments too. It's heavy as hell and I love it. I also have a Husqvarna motorcycle :-)
I gave my 195s Singer straight-stitch machine to my granddaughter, but I bet she never uses it. Those things are bulletproof too. Things in general were simpler and better back then. OTOH, I haven't tried a new sewing machine so maybe I'm wrong.
That being said, My cheapest-model Brother laser printer has been going strong since 2009. It feels light and cheap, but it hasn't failed me yet and I've run through 2.5 toner cartridges so far. If I were going to buy a new machine I'd probably go with a Brother from WalMart.
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