Skyhawks come in 3 generations
Classic 1956-1967: Powered by the 145 hp 6 cylinder Continental O 300 engine and with old fashion panel layout, and in the early years (pre 1960) straight tails and no back window (pre 1963).
Legacy 1968-1985: Powered by the 150-160 hp carburated 4 cylinder Lycoming O 320. Look very similar throughout the model years and closely resemble a new build but with a cheaper plasticy panel and interior, no corrosion proofing in the airframe, and some structural problems in higher time examples.
New Build 1996 - Present: Powered by a 160 -180 hp fuel injected Lycoming IO 360. Modern and very nice seats and interior, improved updated and corrosion protected airframe.
Prices (UK) range from 15K pounds (Tatty Classic) to 300 K (Factory new)
Which part of the market are you looking in ?