I've had them for two years now and they've helped up well; recently I wear them less because I think denim is more fashionable and I don't need the performance most of the time.
Wool garments, from a small company set up by a Danish ex Jaeger Corps who was aghast with the quality (or lack thereof) of clothes out there when he returned to civil life.
I don't even remember how I got in touch with them, but I was looking for robust, functional yet stylish clothes I could both wear everyday and do skateboarding with. I just remember buying one for the heck of it early in the company life and be instantly amazed by the fit, quality, and how the t-shirt would cater for sports, casual and professional life. I bought about 10 of those, and then their socks and underwear too. I could put up a day-long skateboarding session with lots of sweating, just hang the thing to dry and it would be fine in an hour, so I could wash them once a week when wearing daily, which is impossible with cotton and has a dramatic effect on lifespan. Very breathable, so nice in summer but also keeps you warm in winter.
The upfront cost seems high for "just a t-shirt" but boy have they endured the trial I've put them through over two years. I definitely recommend following their recommendations for washing and drying.
I'm wondering how it'd work with underwear though, as that's probably something one might to wash after each use regardless of material.
I'm not familiar with Loow's products, but since they're wool and people are saying they are of high quality, I don't think $75 is unreasonable.
Costco gets you the best deal, Walmart and the dollar stores only sell garbage at the lowest possible cost, Amazon sells literally everything and has converted over the years from having the best deals to having the fastest logistics, and then there's whatever niche specialist suppliers are left like digikey for electronics parts etc.
Old Navy's clothing has typically been disposable trash. And most of it still is - generally anything they make out of cotton.
But their Old Navy Active line, specifically their "Breathe ON" fabric, is pretty durable and has really kept me cool throughout this crazy hot summer. They also sell tall and extended sizes which I appreciate. Tall sizes are typically so hard to find. These are not heirloom clothing items, but they've shown little wear over several summers.
This is functional clothing, not anything particularly fashionable. And lest this seem like an viral marketing post, let me restate that most of their lineup is still trash.
 I use one of their credit cards to pay for things and the rewards mean I can buy some of this stuff for cost of shipping or less.