Hey guys i got a couple of questions and hopefully someone will answer them

1.i know theres a lot people just max out the attributes according to the three classes,but i noticed that maxing out my int on my eng wont work since it reached its max,can someone tell me which point should be added so that its usefully added?(i am looking the engs hybrid build that allows soloing
2.is there a guide that states the accurate pricing of the stuff in auction, so that the item prices dont go up and down as they like, please send me a link if there is