//given that I only get 15m internet access at a time I will male no effort to correct grammar and typos, if any of it prevents your understanding please let me know//
As someone that has legally downloaded I can tell you that catalouges as usually the most extensive after all digital storage is dirt cheap these days. My main legal down loading is computer games and I can buy and download games decades old that you would just never find in the shops. The main concern is what happens to my access to these items if the provider liquidates? This was a big question when services like Steam appeared on the market., though currently Steam shows no signs of going away.
Usually there are no adds other than the usual store adds for discount sales and things pretty much normal for brick and mortar too. There is no difference in quality, Cd music for example was stored in WAV format at one time, there is an option to download WAVS, though in the past many were MP3s where the file compression did lead to a loss in quality, but most people did not have the kind of equipment for this to be noticeable. But these days "lossless" formats are ten a penny.
There are streaming services such as crunchy roll where you can watch for free ( ads) or pay a subscription ( no ads). Thus they function much like a cable TV subscription minus the ads with the addition of being able to select the programs you want to watch when you want to watch them, watershed limitations do not exist.
To use these services the learning curve is no different to online shopping. Find what you want click a few links enter payment details. There is no special ritual or sacrificing of black cats.
The money is allocation is dependent on private deals. However there are some services such as humble bundle where you can select what proportion of the money you pay goes to the create and the rest is split between humble bundle ( the middle man) and a charity. It is of note that this also happens to be one of the "pay what you want" websites.
The service is pretty standard but Steam was infamous for its uncaring attitude and no refund policy, while direct customer service is not so great, there is now a bare bones refund system. However competitors offer refunds and a trade in system. Steam remains the big boy in town due to it early entrance into the market, but it's market share is being ate at, hence why they suddenly adopted refunds.
I turned to legitimate sources because they are simply a more convenient business model , some appeal to my sense of ethics and minimalism and the prices are much more affordable to me . I cant afford to gamble $60 on a game I know nothing about, but these days I can watch a lets play on you tube, then go to humble and set a price I can afford with a bit to charity or wait for a steam75% off sale. Then I can simply download whenever I want without boxes taking up much need self space. Illegal download of computer games however means finding it, downloading it ( with risk of infection, and may be really slow...... or just dead links), then you have to install it, find or create a 'crack', and then maybe have to find a deactivate for any online DRM ( usually this DRM is in the form of steam codes). A lot of publishers have also amused themselves by adding in little things to annoy those that have illegaly downloaded. Though many publishers ( usually indies) have openly told people it is ok to 'pirate' their game but please give some money if you like it. Though once this permission is given is it really piracy then, or is he offering up his software for free and asking for donations?
Donations and patreon funding have been fairly recent business models , both of them have seen success. With the drop in add revenue from you tube adds, many channels depend on patron funding via the patreon website. A throwback to the past where people like Mozart and Da Vinci did not get paid for albums or painting, but were funded by a rich patron to produce music. Da Vinci also side earned as a weapon designer ( before you get that in)