Search reddit for cover letter threads. There's some good pieces and examples that may be helpful to you.

To me, this sample seems very "fluffy". It has a lot of niceties that people in high school would add into their essays to make sure they made their page length. There's a good amount you can cut out from this to make it more direct and to the point. Imagine writing something for someone who only has 30 seconds- 1 minute to read the entire thing. They don't want to hear about your fancy, and extravagant vocabulary. They want to know who you are, what you can do, and why it is pertinent to their company.

For that reason, your intro paragraph is mostly pretty decent. It introduces your interest and something that you like about the company that attracts you to the position.

Your body paragraphs are very fluffy. For example, you could probably take out "In addition to my own interest in the position," since it adds zero content to your paragraph beyond a lengthy transition. You can probably start with "I’ve spent several years in purchasing, dealing with purchasing, ... " taking care to make it sound like a coherent topic sentence. For body paragraphs, I liked to use "This is my experience and what I did. And here is why I think it would be a great asset to your company" as my plan. It's direct and exactly what people want to hear. I don't have much in terms of jobs, so I took maybe 2 of the most attractive qualities I had and bragged about those. Find what each job description (from the companies) has in common and see if you have that. These are the "keywords" that people on this sub tend to talk about. For my customer support positions, it was things like "Zendesk expereince" and "documentation/knowledge base creation" that got me noticed (one particular job called me specifically because I had managed zendesk software). Find those keywords, and brag the hell out of them.

You conclusion paragraph is not very conclusion-y. It feels like you're trying to just butter them up in hopes that they love hearing people compliment them. After the two major qualities i had, i concluded with a very generic "thank you for the opportunity and I'd love to chat. Please look at my resume and I hope to hear from you. If you have questions let me know" message. And that's really all you need. You don't need all that "I think your company is totally cool and the work environment must be awesome!" stuff.

TL;DR- Cut the fat, write more directly/confidently in a professional manner.

Skeleton:

intro: This is who I am

Body text(s): This is what I can do and why it's so great for your company

Conclusion: Thanks for reading! Call me if you have questions (oh and look at my resume!)