Add to your shopping list one of those grey plastic manual bilge pumps.
Every boat should have one. Even if you never need to bail the boat, they
can come in handy when you have a big bucket of lively panfish and you need
to transfer some fresh water INTO the bucket from the outside. Much easier
than hoisting the bucket into the water, at which point the fish will jump
out, you'll lean over to gawk at the spectacle, your glasses will fall in
the water, followed by you, your wallet and your keys. All for the lack of a
manual bilge pump. :-)

Yes, I have seen it before in a marine supply store. No, I will use a
cut off plastic milk jar for putting water into a livewell. But I can
see the value of using a manual bilge pump to pump out the water from
the bilge area in case the bilge pump fails. Thanks.

Jay Chan