Well taking a photo isn't hard? - Not at all. With today's technology everyone can pick up a camera and take images. A very common comment you get as a photographer


- "Your camera take very good photos" - What should i answer to that, c'mon :P
- "Well, thank you, i have learned it all i know" Technically it isn't the camera who takes the photos, its the person behind it. You set all the settings and compose your picture right?. You get the drift.

Is it hard to get your photos accepted at the agencies? - Sometimes. Some agencies are very picky, some are more "relaxed" and almost accepted every picture you submit.

What sells?- Everything, people, nature, editorial, sport, architecture, household items, animals, food

Should you keep on uploading photos even when you get rejected? - Of course.
You should never stop upload photos even tho some of your photos gets rejected. Never take it personal, the editors of the agencies only accepted top quality photos and knows whats sells. You may not always agree with the editors, you can always re-submit the photos you think have potential to sell.

Do you need a camera and lens for 10000$?
No, all you need is a point-and-shot camera. Those are underrated today. They can actually take photos decent enough to make it in stockphoto market.
What camera gear you use does not matter to much, its HOW you use it that counts.