Honestly, I'd say with a child that really the snake's personality will need to be what's focused on.
This guy is definitely kinda bothering the snake and handling it a LITTLE roughly, so its behavior at the start is perfectly calm. Seems to be why he's poking at it trying to show it won't get snappy if its manhandled a little. Doesn't look too headshy.
Issue with focusing in on a morph vs personality IMHO is you might get a BP with very high nerves that dislikes being handled, so you may want to try talking to your daughter that to find a BEL in your price range and presumably not an adult and/or male either, you might end up with a snake that doesn't like being handled and needs to be left alone 90% of its life. Make sure she's OK with that reality -- BPs DO have individual personalities and some will never be "handler" animals -- if determined to get such a specific animal from a limited stock that might be available at a show.
Bees do pull from Spider, which is another consideration with this animal. Make sure to ask about the wobble its exhibiting and when it tends to flare up most (when snake is scared, when it's excited about food, etc) and make sure that a varying amount of neurological wobble is something you are prepared to take care of in an animal. A non-wobbly baby may grow up into a rather-wobbly adult, and environmental factors such as stress can also contribute to the animal's wobble. So that's something to read up on and make sure you're ok with for anything related to a spider.
This specific animal's body tone, personality, and health seem fine, in terms of overall "review".
$300 is not bad for a sterling bee, especially a female.