"A Nazi spy?" Of all the scenarios he could imagine for why Spike would be here, that would be... not one of them.
He shakes his head with a bemused smile, and then shrugs, letting out a breath and spreading his hands. "Sure. Why not?" He starts to go for his wallet and then pauses, lifting an eyebrow. "You'll have to buy, though. I don't have any currency for this time period."
It's a bit of a challenge (as it always is, with them). There's no real reason he'd expect Spike to have the right money either, but he's still asking.