1 Paris: They gave you a mass spectrometer so you could check it was really helium-5?
2 Paris: Do you not see what’s going on here??
3 Serron: Oh... yeah... wow...
4 Serron: I got a free mass spectrometer! How much are those things worth?!

I did a brief bit of searching, but it's hard to find actual prices for mass spectrometers, because the scientific instrument companies that sell them new don't quote prices on their websites. It seems to be one of those things that you need to contact the manufacturer to even learn the price of.

I did find some other sites that quoted prices ranging from $0 (yes) to $400,000+ (presumably US$). So... it's gonna be somewhere in that range, I guess. They seem to come in a very wide range of types and capabilities.