When I held the purse strings and vendors would knock on my door, I was reluctant to book time to see their slides or webinars. I found it more productive to get a brief description of the data, the kinds of things they thought it could be used for, the general pricing regimen and then I'd ask them to demo a value-added solution.
Specifically I'd pick one or more actual projects I was then working on and ask them to demonstrate their product's value by answering a specific question requiring a specific usually formatted presentable output and compare it to the ones I was generating already using other approaches or sources. I'd also ask them to compare their product to its competitors in terms of methodology, timeliness, qualifications and continuity of the compilers, etc. If that went well enough, then I'd see the webinar and make a final determination. Most didn't know their competitors. Words rarely matched performance.
The selling process has to be about first deeply understanding the clients' specific needs, decision process and industry dynamics. Don't sell to clients who don't know that information. They have to be close to the pain and the action. If the product works well in solving real problems and making them a more viable competitor in their industry, it sells itself. The budget will be found.