cblinton has once again hit the nail squarely on the head.
I have just come out of a four year stint of being the sole owner/operator of a 172 and a PA28/161.
The average cost per year (bearing in mind I own my own hangar and fly 100 hrs/yr) was £9650 per a/c.
Good luck!
I've sold them and moved on to proper flying now and I won't look back in anger 'cos I did have some fun.