Stop shopping for "a man" and start shopping for the specific one
The problem with most gift guides for men is that they treat all men as one enormous blob of guy. Beer accessories. Grilling tools. Socks with a pattern on them. These guides exist because they're easy to write, not because they're useful. If you already know the person well enough to be buying him a gift, you probably have enough information to do better than a novelty bottle opener.
Everything below is under $50. Some of it is well under. And instead of a flat ranked list, these are sorted by the kind of person you're actually shopping for - because "the guy who reads" and "the guy who watches three car YouTube channels before bed" do not want the same thing.
The guy who has a system for everything
You know this one. His desk is either immaculate or organized in a way that only makes sense to him. He has strong opinions about pens. He probably uses a physical notebook even though everything else in his life is digital, because he claims it helps him think - and he's not wrong, but he mentions it a lot.
A good notebook is genuinely useful to this person and he will not buy one for himself because he's still "finishing" a half-used one from two years ago. Something with decent paper weight, not too precious-looking, around $15-20. Leuchtturm1917 and Midori both do pocket-sized ones in that range.
Small wall art is another strong option here. The desk-system guy usually cares about his environment but hasn't gotten around to hanging anything because nothing felt quite right. A framed print in the 16x12 range - something typographic or a clean map print - sits nicely on a desk shelf without requiring him to drill holes anywhere. You can find framed art prints starting around $29 that ship flat in a box rather than rolled in a tube, which means they actually arrive looking the way they should.
The guy who never buys himself anything
Different from frugal. This is the guy who has been meaning to replace his worn-out hoodie for eight months and keeps not doing it because something else came up. He doesn't think of himself as someone who "needs" things. He'd feel weird spending money on wall art for his own place even if he'd genuinely like it.
He's the easiest person to shop for once you figure out what he is, because the bar is "slightly nicer version of something he actually uses every day." A good mug - actual ceramic, something with some weight to it, not a thin diner mug - sits in that sweet spot. He'll use it every morning. He'll think of it as his mug. That's a gift that earns its keep over about four years of coffee.
A hoodie in a neutral color, from a brand that doesn't feel like an event souvenir, runs $35-50 and will actually get worn. Champion and Carhartt both have basics in that range that don't look cheap. Avoid anything with a large logo across the chest - this guy is not a billboard person.
The guy who spends half his life in a car
Could be a commuter, could be someone who genuinely loves driving, could just be someone whose job involves a lot of road time. Either way, his phone is doing a lot of work - navigation, music, podcasts about things you haven't heard of. A solid phone case matters more to him than he admits because a cracked screen is a real problem when you're relying on that phone for directions at 7am.
A decent MagSafe-compatible case (if he's on iPhone) runs $25-45 and is the kind of thing people research for two weeks and then don't buy. Getting it done for him is actually thoughtful, not lazy. Check his phone model first - this is one of those cases where "I saw it in a gift guide" doesn't cut it as due diligence.
If he has a dedicated space in the car that's become weirdly personal to him - and some guys do, it's basically a rolling extension of their personality - a small print for his office or home with something car-related or city map related can hit. Anyway, that's only if you know he'd actually want it on a wall somewhere. Don't overthink it.
The guy who's moved somewhere new
This one gets missed a lot. A guy who just moved to a new city or a new apartment is quietly living in a place that doesn't feel like his yet. He's sleeping on sheets he's had since college. He has one (1) piece of wall decor, probably a poster he's had since 2015 that he keeps for sentimental reasons and is now slightly embarrassed by.
Wall art is doing real work here - not as "decoration" in the abstract sense but as the thing that makes a space feel like somewhere a person actually lives. A canvas print in a 20x16 or larger format makes an impression without requiring a gallery wall setup. A simple framed poster works too, especially if you pick something tied to a city he cares about, or something that fits what you know about his taste. Under $50 is very doable in this category.
The mug also applies here for the same reason. Something that is his, in a place that's still becoming his.
One thing worth saying plainly
The under-$50 bracket gets treated like a consolation prize, like you're apologizing for not spending more. It shouldn't be. A $29 framed print that actually fits where someone lives beats a $90 gift set they'll put in a closet. The budget is not the point. Knowing the person well enough to pick something real - that's the whole thing.