The water under the floorboards is normal. The area under the floorboards (which are referred to usually as "the sole") is called the bilge and it is unusual to find a bilge that is completely dry.
The bulkhead seperating from the hull could be anything from a very minor thing (if it just started) to a serious issue. With the condition of the market right now - I would suggest that you keep looking. There are too many really great boats out there to settle for anything dicey.
Repairing small boats is not usually that costly in terms of materials, but the cramped quarters make it difficult to work efficiently or neatly. After making a repair it is frequently necessary to cap the project by refinishing significant parts of the interior or exterior in order to make the boat look nice again.
This refinishing can add a lot to the cost of the boat.