I was really wanting a complete primus "dont really care about unicrons head tbh", but the ebay auctions are fairly high on even the ones missing parts. Anyone know when would be the best time to recheck? Because I know you can get a unicron for fairly cheap "I scored one for 20$ and it was only missing dead end". Also what is the chances that takara and hasbro might reissue the mold in classics 3.0?

Some of the best deals on eBay are that way because they are hidden. Some people have the figure, want to sell it but don't know enough about it to make a listing that will get the top amount possible.

Sometimes you can type 'Transformers Jet' or even 'Transfermers Jet' in the regular search or the 'exact word' option on advanced search and find a cheap Jetfire, Starscream, or even Megatron (Magatron for some). I found a beautiful and complete Matsushiro Jetfire variant for $30 this way. It was listed as "F-14 Tomcat" and the pic was only of the bot with no mention or picture of any accessories. When Jetfire showed up at my house he was 100% complete.

I found a MISB G1 Jazz that I later had AFA graded at NM 85. He was listed under the Die-cast model section as a 'Martini Porsche'.

 

You might try searching misspelled names/words or, for Primus, Transformers Planet or some variation of that.