scope under $400 for wildlife watching needed

Rookie here. So planning a family trip to Yellowstone and would like a decent spotting scope for checking out the wildlife that isn't in the middle of the road. Weight isn't a big concern since it wont go too far from the car. Zoom would be nice. Easy for a 10 year old to use will also be nice. Recommendations will be appreciated! Also websites recommendations will be appreciated, I've bought photo gear from B&H and competitor but I'm sure other places have better prices on spotting scopes.

Richard

Have you considered that perhaps binoculars would be better suited to the kind of trip you are planning?  They wouldn't need a tripod/window mount and don't require any set up at all. 

The 6x30 and 8x30 Leupold Yosemites were actually designed specifically for children to use.   They sell for under $100 and even many adults think these are the "bee's knees."  You could buy enough of these for yourself, your wife, and your child and still not break your $400 budget.  Then everyone can be looking at and enjoying the wildlife at the same time.

If you are sure about a spotting scope, I would suggest something fairly small.  The 60mm Bushnell Elite mentioned by CFII would be good.  Other options within your stated budget would include the 50mm Leupold Gold Ring, Vortex Nomad or Impact, Brunton 50mm Eterna, Kowa 500 series, or Stokes Sandpiper.  And don't forget a decent tripod and/or window mount.