Unless you're going to do over 50 hours a year with each flight being over 2-3 hours, then don't buy an aircraft with retracts e.g. an Arrow, a PA28 variant.
Unless you want to lift 4 adults, don't buy an aircraft with a VP prop e.g. a Reims Rocket - a 172 variant.
Both the Arrow and the Rocket have significantly higher maintenance costs, which can only be justified if your 'mission' demands the performance.
So, less than 50 hours a year, get a 'simple' 172 or a PA28.
The most cost-effective 172 is the 'M' model, difficult to find now, sought after. The older 'H' is lovely with the Continental O300 but will be over 50 years old but my favourite 'simple' 172. Steer well clear of the 'N', the least pleasant of all the 172's.
The most cost-effective PA28 is the old 140, there are some renovated ones around in really nice condition. The later tapered wing Warrior and Archer II are going for ever-increasing prices, they'll all have high hours and there is a potentially expensive spar inspection coming up, depending on cycles/hours/age formula. Most ex-school aircraft might fall foul of this inspection when it materialises.
Spares seem readily available for both makes, they've both been made in large (for aircraft!) numbers over the years.
Our friendly moderator mentions the C150/152. They are 2-seater with limited payload capability. Personally I'd rather fly the 150 with the Continental O200 but you'll be pretty cosy with a passenger unless you're of more modest proportions. You might be more limited by the weather and by the length of trips you might do. I do like the 150 we've got in the hangar for local good-weather trips (the owner likes me to fly it occasionally to keep it fettled - not a chore!).
We're presently in the process of renovating a 1974 Archer with paint-off respray and a factory engine. Should be worth somewhere North of £90k when finished, just to give you an idea of how prices have gone up recently.
Hope this helps a bit.
Cheers,
TOO