The operator that publishes its rates in full, which makes it the easiest to plan around: the standard Nazca Lines flight is US$180 from Nazca or Ica and US$220 from Pisco; the extended 23-figure flight is US$330; flight plus sandboarding US$140; a Lima–Nazca–Lima full day US$369; two days from Lima US$449; and Nazca combined with the Ballestas islands US$410.
Flying from Pisco costs more but saves the long drive down the Panamericana if you are coming from Lima.
MINCETUR-registered as Alegría Tours Perú at Calle Lima 168 — both the address and both phone numbers on the site match the register.