The economics;
If you get a share in a permit aircraft you are looking at typicaly;
1/5 Jodel £3000
£35 per month
£35 per hour
Small risk you will have to pay something extra if the engine fails, but this would mostly be covered by the engine fund if the group is well set up. You are likely to get £3000 for the share when you sell. There are many more similar comparisons but without more info it is hard to quote the right one for you.
Compare the above with the cost of a 152, and decide how many hours you plan to fly.
The practicality;
Main advantage of a share (or your own machine) is availability. You can usually take a group aircraft away for a week a year and it will be normal to take it away for a day at a time. This will allow you to get more from your flying, and you will do more hours. I was involved in several groups from 1991 to 2006, and averaged over 50 hours a year. I could not have afforded to fly that much if I had rented. In that time I also never had to pay “extra” to fix a fault. I now run my own machine, on a Permit.
Rod1