Samy, unfortunatley you have asked a question with limitless answers, as people with different experiences will have different recommendations and feelings....me included
Personally I use an Aqua C Remora Pro for my 75 and really like it. For a 30 you could easily get the smaller Remora model. They are, IMO, some of the easiest and most practical skimmers I have ever used. If there was ever a "set it and forget it" type of skimmer, this one is the closest I have found.
The Super Skimmers are great values for the dollar and are commonly referred to as high quality skimmers, but from experience and from what I've heard they are 1) bulky if you plan to use it HOB style, and 2) finicky as water levels in the tank change. IMO, they are best used as skimmers to be placed in a sump, not HOB, but are still quite effective HOB if you don't mind the bulkiness.
IMO, you get exactly what you pay for with cheaper skimmers and will be back to buying a good skimmer within a couple of months. You can buy a Coralife Super Skimmer on line for about $110-$120, maybe even cheaper if you went with the 65 model instead of the 125 (which you could easily do for a 30). That would be the cheapest I think you would be able to get a high quality skimmer, again, IMO.
I also hear ASM's are awesome skimmers, but I have never had one or used one, so I can't say much about those.
Buy the best one you can for your dollar. Try to stay away from cheap models (i.e seaclones) as they tend to be very very inconsistent and frustarting to work with as most people tend to make a ton of mods to them and are constantly adjusting things just to get the cheaper ones to work how they want them to. IMO, it's just not worth the hassle.