I realize this is rather old, but I've had my radioshack solder sucker for at most 3 months, and a rather nasty design flaw has become apparent.
The top of the plunger is made of a very brittle plastic, and in the process of retracting the plunger head strikes a plate of this this blue glass-like plastic, causing significant mechanical stress. My pump is probably at the end of the road due to this problem, and I'd expect the thing to last at least long enough for the tips to wear out for the $11 price tag. Here are some pictures of the problem.
I'd advise everyone to STAY AWAY from this thing. All of the negative reviews reference this problematic design, and for $11 you can get 3 equivalent ones, or a nice full metal bodied one. There is no reason to spend that kind of cash on such a cheap product.
I'm (obviously) in need of a new one, but don't want to shoot myself in the foot again. Can anyone vouch for a specific plunger type solder sucker?