Is this a good buy?

[Tobias]

I spent 30 Euros ($28) for the "Sky Raider" Trilogy. Is this a good buy?

 

[Father Fletch]

I think you got a good deal on some classic Keith Brothers Traveller material. I also think you paid about market value for material of that era and especially since you did get the set (3)

 

[T. Foster]

That seems pretty fair to me. I've seen them go for a little less ($5-6 each), but I've also seen them go for a lot more ($20+ each). But most importantly these are three really great adventures, and if you've never read/played them before you and your players are in for an enormous treat!