After introducing the topic we see what is needed to make quality photos
Microstock agencies have high standards of quality. This means that the image, before being accepted and made available to potential future buyers, must pass the examination of the agency inspectors. Qualitative standards are in the reach of all those who want to dedicate themselves to the right commitment, but also sufficiently high to squeeze navigated photographers and with years of experience.
A good photographic equipment is not the solution to all problems, but it facilitates and speeds up the work. I’m currently photographed with a Sony a68 with lenses of the zeiss series that I paid right through the microstock sales activity. However, I realized my 2013 bestseller photo with an old sony a37 with plastic lens (today you find everything about 300 euros used on eBay).
In short, just a decent reflex and you do not have to spend thousands of euros. If you really want to make an investment, rather than in photo gadgets I would personally suggest investing in a good course of photography.
A purchase that is really useful is that of a good postproduction software. Among the hundreds available I suggest Adobe Lightroom as one of the best possible choices.