I think the amount is actually overly generous. A lot of the people you contact won't even realize they can make money online. So 30 bucks a month is a lot.
The problem is people will get the impression your operation / intentions are a little shady. You need to humanize your message and explain what you're doing. You don't have to tell the truth or give all the info but you need to explain something.
I think it also depends what you're promoting. If it's ring tones for instance their initial thought might be "spammer" and not want to have contact with you.
So overal you have to get by this preconceived notion that IMers are shady spammers out to steal your paypal info.
The way to do it is humanize your email, explain what's happening, and talk to them specifically (don't send the same canned email to all).
So, for instance, let's say you're promoting a make money blog.
Example...
Hi Marie!
You don't know me but I'm a fan of your channel. I remember watching your video on How To Save Money On Electricity 5 months ago. Since then I've been a fan!
I have a small blog on how to make money online. Only a hobby but I have fun! I'm trying to drum up more readers for my blog and my daughter gave me an idea so I thought I would ask you. If I pay you a fair amount would you be willing to add me to the annotations in some of your videos? I'm not very web savvy so I don't know how much to offer! If interested though, please get in touch. My grandaughters are here with me this weekend but I will certainly reply back to you come Monday morning, if not sooner.
Best Regards,
Sylvia.