I'm betting it's a Berlin 60 and, unless my memory is failing me which is entirely possible, you can buy it new for about $30.00 from www.aquatictech.com
. $50 is way high for this skimmer.
The small Lee would do just fine in your tank. Both it and the Berlin are "in tank" models. If you're gonna do a sump, I'd look for one of the small venturi skimmers...you could run the small SeaClone in the sump with some plumbing changes...I think they're set up to go either in sump or HOB
. There isn't really room in a 7 for an in tank skimmer. If you're willing to do a water change once a week, you probably don't even need one. JMHO.