My suggestion to OP is to first decide the fundamental body type, which can take interchangeable lenses...

Single lens reflex
Twin lens reflex

In all three types there are mechanically timed shutter mechanisms
In the SLR there are electronically timed shutters in newer models in addition to mechanically timed shutters in older models.

The suggestions so far are all over the map, because the OP has not sufficient bounded the search parameters.
'Inexpensive' is not necessarily confined to much older cameras...You can get into a fairly modern SLR like the Bronica ETRS for about $300 with lens(es), about 10% of the new price 15 years ago.