Installing a lockbox is not a tough task. You also don't get paid jack for them considering the cheapest you'll find them is in the $11 - $12 range. I've even heard of some nationals paying just for the cost of the lockbox because installing them takes about 30 seconds. I'd never do it for that much, but I know there are suckers out there that will. So to guarantee that you make a little money on these, make sure you properly document the code and keys that you'll be putting in there. That way some guy at a desk half way across the country can't tell you to go and redo it because somebody couldn't figure out how to open the darn thing, or the last person that went there took the keys with them. Protip: Don't forget to put the key in there for a padlock if you used one on a shed or something. Too many of these come back to me with my guys forgetting it.