You can do the presentation yourself with Camtasia studio, and then hire a narrator with a better voice to record the sound again.
You can also find very budget friendly guys on VideoHive.com's forum to polish your presentation with a some clean background music (i use audiojungle.com), an intro and maybe some clean transitions.
last year i went through this research and found a few firms but this type of work can be expensive, 5k - 30k (30k was from the firm that does the presentations for google and facebook).
While doing my research i found that most viewers are interested more in the content then the presentation. The key is to make sure your content is what you want to convey, and have a presentation that is professional, but it doesnt have to be avatar.
If its for your Azure product that you need a presentation for, then its likely the folks who view it are looking more for substance than pretty colors, music, and effects.
Write your own script, Record your own screenshots, then hire someone with a nice voice to repeat your words for a professional voice over. Put the slight background music, and maybe a few transitions and you are in business.
Best of luck on your ventures~ :)