I would say depending on how it presents a .5 Tec 33 is worth about 2-5K max. This Tec 33 you point out on Comiclink is an exceptionally nice presenting .5, and appears to be a .5 out of technicality (the detached and split cover would be 1.0, but that combined with the chunk out of the back appears to have pushed it over to .5)
In this one instance, because it presents so nice, I think the 5K is justified.
There's got to be a floor on everything. These kind of .5's are very uncommon "diamonds in the rough"
I sold a Tec 35 much in this same shape (detached and split cover and first wrap) and was restored as a .5 CGC and got $5100 back in early 2011.
In my opinion a true Tec 33 2.0 is worth roughly 8-10K depending on how it presents. That 2.0 that sold did not look bad but not great and the wretched case may have hampered its appeal. (I can't stand those cases and might even skip a book just because of the wretched case - can't store those conveniently at all and looks terrible). So the $7,000 or so made sense on it there.