Mr Average has a good point. Another club would not be allowed to set up in competition at my local field. Even if you were permitted to do so it probably would not be worth the aggro.
You would ideally have a bar and cafe or restaurant at the airfield. If it was yours you may actually make some money.
C172 or PA28 are the sensible choice. They have 4 seats and you can train in them. The C172, especially the 'S' models are good short field machines but the customers prefer Pipers. One of the schools nearby have tried every type you could think of over the last 30 years. Trago Mills, Grob 115, DA20 ARV, and a few others. Whilst the C152's have gone the fleet is still mostly Piper Warriors.
As TOO has already pointed out the aircraft have to do a substantial number of hours due to the high fixed costs. I reckon my Archer, 15 years ago cost £10000 per year before it flew.
Finally, one of our three runways is grass and on average it is usable 9-10 months of the year and is very labour intensive.