>>922422cont
I forgot to say in the previous post, beware of MDF interiors (especially if newer than the boat). They absorb moisture from the atmosphere, swell up and lose their integrity.
Boats need Antifoul paint on the bottom to prevent plant and shellfish growth, and sacrificial anodes (usually zinc) to protect the rest from corrosion. Most people here redo these annually, but it will vary on your climate. It will likely be worth repainting the underside while the boat is out of the water for inspection before you buy.
Ask the marine engineer about your specific engine, but common problem areas are oil, heat exchangers, water pumps and corrosion in the exhaust. This last one is one of the more common causes of boats sinking at the mooring. Beware of moisture in the fuel, drain the bottom of the tank regularly. Run your engine at least monthly or the bores are likely to corrode over time. Check your damn anodes. Close the water inlet when the engine's not running. (These all apply to inboard engines specifically, outboards have their own rules)
If the boat has a refrigerator it will probably use an engine-driven compressor, so you will have to run the engine a couple of times a day to bring the temperature down.
The best way to learn to sail is on someone elses boat. By and large yachties are friendly types, so it shouldn't be hard to find someone willing to teach you the basics. Here the coastguard offers dayskipper courses, which I recommend to anyone that sails. Get an experienced sailor to come with when you first take your own boat out, and don't go until you've already sailed in at least 20 kt winds. Always be aware of the weather forecast and don't go out when it's bad.
And lastly, don't expect to make money on any improvements you make. Returns will be 10% at best. Do them because you want them (or to avoid drowning).
Welcome to the fraternity, and best of luck