Instead of letting users access the more comprehensive videos for free, use a service like Wistia Turnstile to created a gated video so people have to submit contact information before they can view the content. This can also be done organically by utilizing YouTube Cards, including a call to action in the video description, or by having the individual in the video or a voice-over asking viewers to contact you to learn more.
I have already mentioned this one in the previous paragraph, but this is something that has to be stressed. While many kinds of online promotion and marketing are cheap and do not require a lot of investments, email promotion is by far the cheapest of them all. All you need to do is hire someone to operate your mailing lists and you will have a full marketing campaign at your disposal. Just make sure that you hire someone who knows how to do this in an organized fashion. You can start for $1 initially with Aweber marketing tool.
A Solo Ad Is An Advertising Method (An Email List Rental) Where The Buyer (You) Purchases A Solo Ad From A Solo Ad Provider. The Solo Ad Provider Sends His Email Subscribers Or A Segment Of His Emails Subscribers A Targeted Email With The Buyers Website / Affiliate / Offer Link In Exchange For Compensation. Typically Solo Ads Are Purchased By Unique Clicks. Solo Ads Are One Of The Fastest Advertising Methods To Drive Targeted To An Offer.