400's may be available down to that price, but the 412 is the last of those models and more expensive.
These are cheap nowadays mainly because
(a) they are 2+2's (really 4-seaters) and so are less sought after than the 2-seater models, and
(b) the "A's" (eg 400A, 400iA) are autos, and
(c) they probably look less like your typical Ferrari, being fairly large & "boxy", although still with great style,
but most importantly
(d) they run a front V12 engine that is very expensive to work on. If you spend all your money just buying one of these then IT will spend all its time in your garage. If you're on a tight budget then keep clear of such a complex car.
My suggestion: look out for 308GT4 models (1974 - 1980). They are also 2+2s, but look more like a 2-seater. They are the forerunner of the whole 308/328 series with respect to engine / gearbox / suspension / brakes / etc, and so are more reliable. They run a 3-litre V8 mid-engined and can be readily worked on by most mechanics, and they go well. They are the best overall value IMHO. Check the Models section in this site for more info.