Solar pannel for batteries

[mushman]

I've had one of those 29.99 solar pannels from west marine for 2 years on one of my batteries.
It seems to keep the charge up but the battery dies quickly.It may be that the battery has crapped out, and the pannel keeps recharging it a little.I don't know.
I just recently got a starting battery and was thinking about buying another 29.99 pannel to maintain the charge, but I'm not sure if it's worth it.
The next model up is like 75 dollars, but it kicks out more amps.
Does anyone have any experience with theese things?.
Are the small one's worth buying, or is it better to spend the extra for more amps?.