I've been getting lots of packages lately. Just got an iPhone 4s yesterday. Should be getting some Galaxy S3s in later this week. Already have some lying around. Can't wait until I can justify an iPhone 5 (maybe when the 5s comes out?) and the Galaxy S4 (universal remote built-in sounds cool).
I'm trying to buy low and sell high. I have a special budget in EEBA, whenever I buy something phone related (be it an actual phone, a replacement screen, some empty boxes, whatever) I deduct from the balance. When I sell one, I add it back. I'm still in the negative, but also just recently started doing this (I have a bit of a surplus I'm planning on selling off). It's important to keep track of EVERY single purchase. Sure, you paid $180 for a phone and sold it for $300; but what about the phone you paid $320 for, bought a box for $6, charger for $3, sold for $330 but had to pay $7 in postage?
Ideally my "phone" account will go back to a positive balance, then I can buy whatever phones I want completely guilt-free (as long as I keep selling the majority back for a profit, thus keeping the account in the black). For me this would be a win-win-win; I'd always have a new(er) phone for "free", I'd be doing something enjoyable in my free time (I love doing the research, and the repairing), and I'd make a little extra cash.
And perhaps buying gadgets is his way of staying current with technology. If I were working in the computing field, it'd be easy to stay current (work would provide me with a brand-new laptop and phone every year or so, I'd get to play with the newest hardware and software when testing out new products before deployment, etc.). But staying at home with kids, it's kinda hard to justify buying a rack full of networking equipment and a new phone every 6-12 months (believe me, waiting every six months was already torture...we really want every new phone on launch date, just so we can tinker with it).
I guess as far as actual advice, I'd try the whole buy-low sell-high thing. Find what the prices on Craigslist and eBay are, then keep an eye for good deals. Keep track of every single purchase; not only will this help keep you from going overboard (wow, no idea I spent THAT much!), it'll help you know when you're doing pretty good. Also, having a misc budget is really helpful (call it an allowance if you want, though I don't like the connotation). I get $50/mo, you could set it to $50/wk, $500/mo, whatever. But whatever it is, there's no strings attached. You/he can spend your misc money as you wish, be it a Big Mac, new shoes, yet another iPhone gizmo thingie, gift for the deadbeat BIL, whatever. If the money came out of the misc category, there will be no nagging allowed (but if he goes over his budget, then let the nagging commence!).