I'd order an Aura, but wouldn't tell him.
After you got it, drop some hints that you are "considering" the Aura, but only if you can find a good home for the Glo. "Maybe I can sell it, or give it to someone who's done me some favors lately". Make him do some more chores, but not as an order. Just drop some hints that you didn't get around to something.
You seem to want that Aura. He seems to want the Glo. Play the game
He's bound to do some (extra) nice stuff somewhere down the road, and then you can surprise him with the Glo as a reward.
It's a second-hand reader, but maybe he doesn't have one now; or if he does, that it's a nice upgrade to his current one. If he sells his current one (if he wants to), it nets him some extra money too.
All assuming that you can spare the money.
It's quite an ideal situation. If a new reader comes out that you'd want, then you can offload your old reader to him. It keeps his reader fairly current without it you costing extra money. That his reader will always be one, maybe two versions behind yours isn't a problem. It's a good way to learn that you don't always get to have (or need to have) the latest and greatest, especially if you're not paying for it yourself.
At least, this is the way I'd do it.