Stealth Seminar – $97 first month then $69.95/month – http://www.stealthseminar.com/
We use Stealth at HECP right now, but have had some tech issues related to mobile browsers and outdated flash video technology. Stealth support is excellent and will help setup almost all of the webinars under your direction. All in all, a solid choice

EasyWebinar – $66/month (Pro) – https://easywebinar.com
Currently testing this platform with promising results. Easy to use, reliable technology. Limited internal registration page templates but does provide an easy to install registration widget that can be used on almost any website for a fully custom registration page. It appears that the annual plan we are on is no longer offered.

WebinarJam – $479/year – https://www.webinarjam.com
Live webinars and replay of live only. Advanced system with many templates and integrations. Limited support offerings but interface is very user-friendly.

EverWebinar – $497/year – https://www.everwebinar.com
Same company as WebinarJam but for Automated webinars only. Can also directly interface with a WebinarJam account to convert Live webinars to Automated/Evergreen simply.

Demio – $154/month (Growth) – https://demio.com/
Newer system with solid feature set. Not a lot of direct experience running webinars here though.

WebinarNinja – $49/month (Starter) – https://webinarninja.com/
Similar to Demio. Newer with solid feature set. Limited direct experience.