Old pentax K, M, and A's manual focus do fit with auto stop down.
Old pentax/asahi/takumar M42 lenses also fit with an adapter but no auto stop down.
(I collect both styles of lenses)
Old Pentax KAF mount F's, F's, and FA's (80s Autofocus) fit without an adapter.
DA lenses of course will fit too... but not on film cameras.
My observation, most new photographers get frustrated rather quickly with manual lenses on DSLRs simply because they see how easy the photog next to them has it with AF lenses.
If you are new to photography and on a tight budget, I would just recommend getting the kit lenses to start out with. They aren't "that" bad to start and you can learn lots with them. Once you advance, you'll know exactly what you want; maybe higher speed zooms, maybe a super zoom with lots of range, maybe nice set of primes, or maybe a collection of vintage manuals. You won't know until you get some experience and enjoy some.
K10D with kit lenses: 18-55 and 50-200:
IMGP4585 by
usayit_2000, on Flickr
IMGP4613 by
usayit_2000, on Flickr
IMGP4619 by
usayit_2000, on Flickr
IMGP4636 by
usayit_2000, on Flickr