music-buying platforms
This is a list of online platforms that allow you to buy music. I like to focus on buying music from places where a) musicians get the maximum amount of money and b) the owners of a platform aren't scum. Several of the platforms that are listed here are either co-ops or decentralised, both of which are two very nice ways to go, instead of creating the infernal mayhem that is Spotify.
Quboz

Quboz: you don't even need an account on their platform to buy music from there. However, to subscribe to their 'Sublime' platform is to get up to 60% discounts when buying music. For their music-streaming platform and to see how they pay artists, see music-streaming platforms#Qobuz.
Discogs

Discogs is an old-school platform that allows users to list the record collection, track what they want to buy, and most importantly lets people buy music in physical form.
Bleep

Bleep have been around for ages. Bleep is the classic site for mainly—but not exclusively—lovers of electronic music.
They offer not only digital and physical music but also sell merch like clothes and books. For example, Warp and Aphex Twin offer exclusive stuff via Bleep.
Highresaudio

Highresaudio have been around for a long time. They offer a quality guarantee. From their About page:
Designed, edited and operated in Berlin and Hamburg, Germany, HIGHRESAUDIO is the first commercial music download service for audiophiles offering only music recordings in high-resolution audio standard at 24-bit. The selection and offerings are available worldwide depending upon the licensing and territorial agreements with the license holders. Available are only albums in its native sampling rate from 44.1kHz up to 384kHz. HIGHRESAUDIO doesn't offer any up-sampled, technically manipulated and tweaked recordings. [...]
HIGHRESAUDIO exclusively offers high-resolution music downloads in stereo and if available in 5.1 Studio Master Quality in FLAC, ALAC, DSD, DXD-FLAC and MQA format for an immediate download ("Instant Download").
Highresaudio also offer music for streaming.
Boomkat

Boomkat have also been around for ages. They're always interesting. From their About page:
Boomkat Limited is a specialist, independent online record store that has been trading since 1998 when we opened up a record store in Manchester called Pelicanneck.
We have been online since 2002 and in that time we have supplied the finest Vinyl, CD, Cassette and Download releases to customers in over 100 countries.
Our focus is not on any one particular type of music; instead we are constantly on the lookout for what we consider to be the most innovative, exceptional, interesting and often overlooked music out there - regardless of where it has come from or who it is made by.
Mirlo

Artists get to decide how much of their sale goes to Mirlo. They do this by setting a percentage on sales. So if an artist sells an album on for $10, they will decide whether Mirlo gets 70 cents, $1, or nothing. This lets artists decide how much of their money they need for themselves. By default, Mirlo charges 10% on each sale. Then, our payment processor Stripe, will take a cut of 2.9% + 30c (proportionally this is larger on small transactions).
Want to know more about our thought process? Check out our blog post explaining how we got there.
As we develop our project and come to terms with the costs of running it, we will adjust these numbers and explore new ways of financing Mirlo.
A few people who used to work with music-streaming platforms#Resonate now work with Mirlo.
Jam

Jam:
jam.coop is a new online service that allows musicians to connect with and sell music directly to their fans.
We plan to have features similar to other services, such as Bandcamp, but with a crucial difference: jam.coop is a co-operative run by and for the benefit of musicians and the people who build the platform. We're not for sale and never will be.
To cover the costs of running and building jam.coop a 15% fee (minimum 20p) is taken from each sale.
We're not sure what the best fee structure will be in the longer term - we need to balance sustainability, speed of development and fairness. We'll be entirely transparent about our finances and involve musicians and workers in the decision of how to set these fees.
Ampwall

No ads, no data sales, no AI music, no crypto.
Independent music is too important for one single platform (we're talking about Bandcamp) to dominate everything, especially after being sold twice in two years. Besides, they've been around for a long time and haven't made any major upgrades in a very long time. It's time for some new energy.
But we're not at all interested in just being a Bandcamp clone. We have different ideas about what a music platform should be. We lay out a lot of reasons in our mission so read that for the full story.
Bandcamp

Unfortunately, Bandcamp have been sold and bought by venture capitalists that dislike union work for the benefit of their floor workers.
However, Bandcamp Fridays is still very much a thing. On these days, Bandcamp waive their usual fees and transfer 100% of their profits to artists.
Bandcamp also work as a music-streaming platform.
Artcore

Artcore is a DJ-centered platform that's designed to sell music and merch. From their About page:
To provide artist, bands and labels the best platform to sell to and connect with their fans. To provide DJs and fans with the best music discovery and purchasing experience.