I know almost nothing about drones.

He's going to be 35, likes to rock climb, hike and bike.  He used to write software for Lego robots.

I'd like to keep the cost as low as possible but have the following capabilities.

1. Return to operator or base.

2. Follow operator.

3. Repairable or replaceable parts.

4. Doesn't need to go for miles probably stay withing 1000 feet of him, I['m guessing.

And as I said I want to keep it as low cost as possible. 

Thank you for any help that you can offer.