| Hello there. We have a little beagle (a year old) here and she does not cost a lot to maintain.
We just bought a 35lb bag of dog food for $365HKD. It will probably last close to 2 months. But a lab would go through that A LOT faster, less than a month probably.
If you are getting a pup, be prepared to get all their necessary shots at the vet. I don't know how much that would cost you here as I did it in the US. I think perhaps all the shots I spent a total of $300USD.
I don't know a lot about pet insurance but I've heard many say it's not worth it. You end up spending a lot of money. Without it, I guess you are at risk though if there are really any serious emergencies with your pet, which would require an operation.
There a lot of little costs you should factor in: dog bowls, treats, poop bags, leash, and toys. You might need to get a crate to help train your pup not release themselves inside your home. I don't know how much those cost here but we got ours for $75USD in the US. | 
