Fifty dollars for D2, a tanto point and a G10 handle is the price bracket where most knives feel like a compromise. The Kubey Avenger KU104F is at least honest about it: 3.07 inches of D2 at 0.12 inch stock, 7.91 inches overall, and a G10 clip.
The spec: 3.07-inch tanto, beadblast and dark stonewash finish, flat grind, D2 at HRC 59-61, green G10 handle at 0.51 inch thick, liner lock, caged ceramic bearings, G10 clip, tip-up and left or right reversible, 4.84-inch handle. Kubey lists it as ambidextrous and the liner lock is not, which is worth knowing before you buy.
Kubey lists a lifetime warranty on the Avenger, which is worth more on a $50 knife than on a $200 one. The G10 clip is unusual and it is a real choice: a G10 clip weighs nothing and will not scratch, but it also flexes more than steel and can wear at the mount. On a $50 knife that is a reasonable trade. D2 at 59-61 is the standard budget tool steel — it will hold an edge better than 8Cr13MoV and it will rust in a damp pocket, so the stonewash finish is doing some of the protection work.
Against the Belus at $80 you save $30 and give up 14C28N's corrosion resistance and a nicer finish. Against the Hamster at $110 the gap is $60 for stock thickness, blade width and titanium hardware. Against the wider budget market the Avenger is competing with the Kershaw and CRKT $50 tier, and it wins on bearings and blade stock rather than on steel or on lock design.
Verdict: a competent first folder or a spare that lives in a toolbox. Skip it if you need a knife that survives wet work, because D2 and G10 hardware is not the combination for it.