No matter what level or place you're at in your job or sport, sponsorships can be a huge asset in your image, your publicity, people's impression of you, and your success overall.
Many athletes, race directors, adventurers, photographers, bloggers, etc. want sponsorships for awesome gear that they know, love, and use, but ALSO for the ability to call a big company a "partner" or "affiliate."
Why? It can help elevate status either professionally or personally and give our skills a bit more legitimacy. It can make you look like you are in-demand, you're being noticed, and you're worthy of a company's trust. I'm assuming status in your industry is important to you or you wouldn't be reading this, and by seeking out one of these sponsorships, you are absolutely more empowered together than alone.
Ambassadors tend to be people that get a bit of free gear or stuff in exchange for some social media posts, blog posts, photos, expo appearances, photoshoots, or something similar. As an ambassador, you will act as as just that (an ambassador) on the company's behalf. Ambassadors are (very) typically unpaid.
2. Full Sponsorships
Sponsored athletes/adventures/bloggers, etc. ARE typically professionals. Sponsorship money is actually quite rare for most people and is allocated to people that may race for the company's team or work for the company in some way. This does not mean that these ONLY go to pros, but if a company is going to essentially hire you to race, travel, perform, or work on their behalf, they will likely want you to be a little more exclusive with them and be known in your community. There are many ways to achieve this, though! So don't be discouraged if you're not #1 all the time!
3. Gear Testers
As a gear tester, you will work with a company to try out new products, test products under pressure or in new conditions, and then give them feedback about how to improve it and the end-user experience with the product. You may or may not be asked to post things on social media, as the company may want to perfect their product before going public. This can be a great way to establish a good relation with a company you DO want to keep working with. These positions are typically not paid in money.
Partnering with a company can mean almost anything. Usually, it is some form of cross-promotion or collaboration where you both benefit from the publicity. This could be a non-profit event partnering with a company to help support a cause where the brand get event publicity and the event gets supported with great gear, or you put each other's logos on your websites with links. There is not usually money involved unless you or the company is making a charitable donation or you are working on a commission system for each other.
Each of these is worth pursuing if it's a company you would be proud to work with. Having companies backing you or your cause can add legitimacy and clout to what you are doing, and you should feel proud to represent or work with the company who has agreed to work with you. The relationship should only get better with age, so no matter where you start or what skill level you are at, it is worth pursuing a partnership if you intend to keep growing or progressing.