Just a note, I heard there was possible future plans for an auction house. I could be wrong in this, but if this were to happen price checks wouldn't be needed as people would bid as they feel the poke is worth - and this would negate the constant effort posting in trade every minute or so and watching it get wiped away in few seconds due to the influx of messages.
The problem with price checks is that one poke could be awful nature/awful iv's is absolutely worthless to one person but someone who has a liking towards that particular pokemon or wants it to complete pokedex would put a considerably higher price on it.
This also applies to sync pokemon. For example, I was absolutely desperate for a sync modest poke, the seller said he had already received a 10k bid, I offered 15k, the other then offered 20k and I eventually bought it for 25k. I know I overpaid, but the modest Eevee I caught later with it paid for it tenfold.
I hope this helps put forth another angle on the matter, but I do understand where you're coming from. :) The whole thing is a bit of an ordeal atm.