Astromech Droid, R2-D2, Flat Silver Dome, Dark Blue Print with Lavender Dots

Comes in 14 sets, made of 4 parts. The lowest-priced set it comes in is 75228 Escape Pod vs. Dewback Microfighters (RRP £17.99).

Check the minifigures carefully when buying a used set: they're part of its grade.