A free alternative is
FltPlan.com Flight Planning & Flight Tracking for General Aviation..
You have to register and then authorise them to submit flightplans on your behalf but that's a once only item. Very, very useful service. I've been using them for 6 years, both privately & commercially ie part 91 & 135 operations.
Many aircraft types are already in their database so once you enter the types & callsigns a lot of flight planning becomes a point & click affair. Similarly weather/notams for a flight or series of flights. They helpfully note planned UTC dep. & arr. times on the weather briefing which makes looking for applicable times within TAFs a no-brainer. For a fee they can even handle the US Customs' eAPIS notification for international flights and Safety Management System requirements (if that applies to you).