You're definitely not locked into the Nespresso ecosystem. We have lots of Nespresso pods, but we've used Starbucks, Avalanche, Allpress, Coffeecapsules2u, there's even a Baileys flavoured one we've tried (original, not Vertuo). My opinion is that Nespresso tastes the best, but there's a lot of options out there and generally they're all cheaper than Nespresso.