I've had more luck with iPlayer than Netflix over VPN--NordVPN works most of the time for both but I've had far fewer failures with iPlayer. VPN blocking is a game of cat and mouse and just like in real life, the cat never catches every mouse.

I have never seen a significant airfare difference with VPN that wasn't either a locals-only airfare that would require local ID (eg domestic flights in Argentina) or an airline that loaded an exchange rate wrong and cancelled the tickets later.

You used to be able to get away with a bit of arbitrage on subscriptions by VPNing to cheaper countries, but most of the big providers have wised up and require payment methods based in that country. Otherwise we'd all be paying INR 119 (about USD 1.50) a month for Spotify.

VPN is great for checking your E-ZPass account from outside North America, getting some stupid webshop to charge your American card in USD for a shipment to Arizona even though you're sitting in Kazakhstan, and (usually) beating geoblocking, but it's not going to save you any money on flights.