If it is flat and level with the discussion on the relationship between acquaintances. If the subordinates and strangers discuss relations

刚读到过一段文章，写得挺好，有些道理。 坐而论道，办法是讨论，你一个观点，我一个观点，侃侃而谈，如坐春风。要合作办事，办法是商量。 讨论重在观点，商量重在态度。讨论者的地位是平等的，商量者则各把对方当尊者。

商量and 讨论both have meaning of talk over/ discuss/consult but "商量"is more use when you talk with your friends ,s"商量"means you exchange viewpoint and opinion,when you buy things you ask for price ,you can say "商量价钱" which means bargain. “讨论” sometimes is more formal.you can use it in similar way as "商量"when you discuss with your friends.but when you discuss in class or some meetings ,you should say "讨论""讨论"is also means debate. and i think the most difference of them is when you say "商量" you want to have a same purpose or outcome.when you say “讨论”,you may more lay stress on the "discuss and difference" all these are my own view,but i hope it can help you .

商量= negotiate 讨论 = discuss

<商量>接近于negotiation <讨论>接近于discussion