...or is it better to spread them around and let the agency decide on price?  I've shot stills for a while but pretty new to videos.  I've read that some places are selling videos for $1.50 or thereabouts, even 4K vids.  It seems to me that it may be better if you stick with places like Pond5 since you can raise (or lower) the price to what you want.  There may be others that let you pick your price but Pond5 is the only one I'm aware of - like I said, I'm new to videos.  What do you guys think?  Thanks.

That's what seems logical to me (assuming you can make regular sales at those prices). 

Combined Pond5, Adobe and SS together becomes regularly, in my case. The place I actually sell most videos is from my now outdated library at iStock, but with the $0.49 it doesn't even come close to what only one sale a month would give me at Pond5.

But does SS and Adobe let you know how much they are selling your footage for before the sale is made?  Is it comparable to Pond5?  I thought SS and Adobe sold videos for much less and also took a significantly larger percentage of video sale.  I don't know for sure, maybe you could tell me.