This echoed pretty much everything I feel. I don't go by any guide either, and I don't think anyone really should.
It's not hard to figure out prices, and usually the one regarding pet prices are completely different to the one regarding the cost of making them anyway.
And while I like Latis, I do agree that no one likes to trade for them. It's a shame since they are adorable, but there aren't enough costumes for them yet to be desirable.