Yorkie-poo

Hello.
One year old Yorkie poo.
Super smart.
Listens to commands, potty trained, loves a good belly rub.
He's use to bigger dogs and has been around lots of people.
He barks.
He barks at noises he hears, other dogs and periodically at sudden movement.
He does listen to his name or the word no and will calm down quickly.
We've only had him 4 months and as much as I love him our big dogs step on him and run him over instead of being careful and I just don't think that's very fair for the little guy.
Asking what we paid for him